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FORGE-PRACTICE 

AND 

HEAT TREATMENT OF STEEL 



BY 

JOHN LORD BACON 

Conslruciion Engineer 

Member American Society of Mechanical Engineers 

Sometime Instructor in Forge Practice and Machine Design^ 

Lewis Institute, Chicago 



THIRD EDITION, REVISED AND ENLARGED 
BY 

EDWARD R. MARKHAM 

Consulting Engineer 
Specializing in Beat Treatment of Steel 



NEW YORK: 

JOHN WILEY & SONS, Inc. 

London: CHAPMAN & HALL, Limited 

1919 



1^ 



^-^^^^ 



Copyright, 1904, 1908, 1919, 

BY 

JOHN L. BACON 



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OCT -4 1919 



PRESS OF 

BRAUNWORTH & CO. 

PRINTERS AND BOOKBINDERS 

BROOKLYN, N. Y, 



©CI.A5851.'29 

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WITHOUT WHOSE ASSISTANCE IT WOULD 

NEVER HAVE BEEN WRITTEN, 

THIS LITTLE VOLUME IS 

DEDICATED. 



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PREFACE TO THE THIRD EDITION. 



Modern demands on the finished products of 
steel have necessitated rapid strides in the art of 
heat treatment of the metal. As the subjects of 
forging, hardening, tempering and annealing are so 
closely correlated it has seemed wise to add to 
"Forge Practice" a certain amount of material 
devoted to the other branches of the art. 

The introduction of heat measuring and hardness 
testing instruments, together with various other 
modern appliances, and up to date systems of doing 
work have made necessary a broader knowledge of 
heat-treating methods than was formerly the case: 
for after all the most important factor is the man 
doing the work. 

It is the earnest wish of the writers of this volume 
that it may be instrumental in helping men engaged 
in heat treating steel to be of greater value to them- 
selves and others. 



PREFACE TO THE SECOND EDITION. 



The author believes that the text book should 
be used to explain principles and give examples, 
not to give minute explicit directions for making 
a set of exercises. 

This necesitates an independent set of drawings 
for the work to be done. 

It is for this purpose that the set of drawings 
is given. 

The author has felt the need and lack of such 
drawings in the text-book as used before, and it is 
to remedy this defect that the addition has been 
made. 

The exercises are such as have been found useful 
in the shop, and an effort has also been made 
to give drawings of such tools as are ordinarily 
used in the forge and machine shops. 

J. L. B. 

March, 1908. 

vi 



PREFACE TO THE FIRST EDITION, 



This little volume is the outgrowth of a series of 
notes given to the students at Lewis Institute from time 
to time in connection with shop work of the character 
described. 

It is not the author's purpose to attempt to put forth 
anytliing which will in any way take the place of actual 
shop work, but rather to give some explanation which will 
aid in the production of work in an intelligent manner. 

The examples cited are not necessarily given in the 
order in which they could most advantageously be made 
as a series of exercises, but are grouped under general 
headings in such a way as to be more convenient for 
reference. 

The original drawings from which the engravings 
were made were drawn by L. S. B. 



CONTENTS. 



CHAPTER I 

PAGB 

General Description of Forge and Tools i 



CHAPTER II. 
Welding 17 

CHAPTER III. 
Calculation of Stock for Bent Shapes 41 

CHAPTER IV 
Upsetting, Drawdstg Out, and Bending ki 

CHAPTER V. 
Simple Forged Work 68 

CHAPTER VI. 
Calculation of Stock; and Making of General Forcings. ... 90 

CHAPTER VII. 
Steam-hammer Work .,.,.. 120 

CHAPTER VIII. 
Duplicate Work , 146 



X CONTENTS 



CHAPTER IX. 

PAGE 

Tool Forging and Tempering , 159 



CHAPTER X. 

Miscellaneous Work 183 

Tables 377 

Course of Exercises in Forge Work ,...,... 387 

Index 409 



FORGE-PRACTICE. 



CHAPTER I. 

GENERAL DESCRIPTION OF FORGE AND TOOLS. 

Forge. — The principal part of the forge as gener- 
ahy made now is simply a cast-iron hearth with 
a bowl, or depression, in the center for the fire. 
In the bottom of this bowl is an opening through 
which the blast is forced. This blast-opening 
is known as the tuyere. Tuyeres are made in 
various shapes; but the object is the same in all, 
that is, to provide an opening, or a number of 
openings, of such a shape as to easily allow the 
blast to pass through, and at the same time, as 
much as possible, to prevent the cinders from 
dropping into the blast-pipe. 

There should be some means of opening the 
blast-pipe beneath the tuyere and cleaning out 
the cinders which work through the tuyere-open- 
ings, as some cinders are bound to do this no 
matter how carefully the tuyere is designed. 

When a long fire is wanted, sometimes several 



2 FORGE-PRACTICE. 

tuyeres are placed in a line; and for some special 
work the tuyeres take the form of nozzles pro- 
jecting inwardly from the side of the forge. 

Coal. — The coal used for forge-work should be 
of the best quality bituminous, or soft, coal. It 
should coke easily; that is, when dampened and 
put on the fire it should cake up, form coke, and 
not break into small pieces. It should be as free 
from sulphur as possible, and make very little 
clinker when burned. 

Good forge-coal should be of even structure 
through the lumps, and the lumps should crumble 
easily in the hand. The lumps should crumble 
rather than split up into layers, and the broken 
pieces should look bright and glossy on all faces, 
almost like black glass, and show no dull-looking 
streaks. 

Ordinary soft coal, such as is used for "steam- 
ing-coal," makes a dirty fire with much clinker. 
" Steaming-coal " when broken is liable to split 
into layers, some of which are bright and glossy, 
while others are dull and slaty-looking. 

Fire. — On the fire, to a very great extent, depends 
the success or failure of all forging operations, 
particularly work with tool-steel and welding. 

In building a new fire the ashes, cinders, etc., 
should be cleaned away from the center of the 
forge down to the tuyere. Do not clean out the 
whole top of the forge, but only the part where 
the new fire is wanted, leaving, after the old 
material has been taken out, a clean hole in which 
to start the fresh fire. 



GENERAL DESCRIPTION OF FORGE AND TOOLS. 3 

The hearth of the forge is genei^ally kept filled 
with cinders, etc., even with the top of the rim. 

Shavings, oily waste, or some other easily lighted 
material should be placed on top of the tuyere 
and set on fire. 

As soon as the shavings are well lighted, the 
blast should be turned on and coke (more or less 
of which is always left over from the last fire) 
put on top and outside of the burning shavings. 
Over this the "green coal" should be spread. 

Green coal is fresh coal dampened with water. 
Before using the forge-coal it should be broken 
into small pieces and thoroughly wet with water. 
This is necessary, as it holds together better when 
coking, making better coke and keeping in the 
heat of the fire better. It is also easier to prevent 
the fire from spreading out too much, as this 
dampened coal can be packed down hard around 
the edges, keeping the blast from blowing through. 

The fire should not be used until all the coal on 
top has been coked. As the fire burns out in the 
center, the coke, which has been forming around 
the edge, is pushed into the middle, and more 
green coal added around the outside. 

We might say the fire is made up of three parts: 
the center where the coke is forming and the iron 
heating; a ring around and next to this center 
where coke is forming; and, outside of this, a ring 
of green coal. 

This is . the ordinary method of making a small 
fire. 

This sort of fire is suitable for smaller kinds of 



4 rORGE-PRACTICE. 

work. It can be used for about an hour or two, 
at the end of which time it should be cleaned. 
When welding, the cleaning should be done much 
oftener. 

Large Fires. — Larger fires are sometimes made 
as follows : Enough coke is first made to last for 
several hours by mounding up green coal over 
the newly started fire and letting it burn slowly 
to coke thoroughly. This coke is then shoveled 
to one side and the fire again started in the follow- 
ing way: A large block, the size of the intended 
fire, is placed on top of the tuyere and green coal 
is packed down hard on each side, forming two 
mounds of closely packed coal. The block is 
taken out and the fire started in the hole between 
the two mounds, coke being added as necessary. 
This sort of a fire is sometimes called a stock fire, 
and will last for some time. The mounds keep 
the fire together and help to hold in the heat. 

For larger work, or where a great many pieces 
are to be heated at once, or when a very even 
or long-continued heat is wanted, a furnace is 
used. For furnace use, and often for large forge- 
fires, the coke is bought ready-made. 

Banking Fires. — When a forge-fire is left it 
should always be banked. The coke should be 
well raked up together into a mound and then 
covered with green coal. This will keep the fire 
alive for some time and insure plenty of good 
coke for starting anew when it does die out. A 
still better method to follow, when it is desired 
to keep the fire for some time, is to bury a block 



GENER.\L DESCRIPTION OF FORGE AND TOOLS. 5 

of wood in the center of the fire when bank- 
ing it. 

Oxidizing Fire. — When the blast is supplied 
from a power fan, or blower, the beginner generally 
tries to use too much air and blow the fire too hard. 

Coal requires a certain amount of air to burn 
properly, and as it burns it consumes the oxygen 
from the air. When too much blast is used the 
oxygen is not all burned out of the air and will 
affect the heated iron in the fire. Whenever a 
piece of hot iron comes in contact with the air the 
oxygen of the air attacks the iron and forms oxide. 
This oxide is the scale which is seen on the outside 
of iron. The higher the temperature to which the 
iron is heated, the more easily the oxide is formed. 
When welding, particularly, there should be as 
little scale, or oxide, as possible, and to prevent its 
formation the iron should not be heated in con- 
tact with any more air than necessary. Even on 
an ordinary forging this scale is a disadvantage, 
to say the least, as it must be cleaned orf, and 
even then is liable to leave the surface of the work 
pitted and rough. If it were possible to keep air 
away from the iron entirely, no trace of scale would 
be formed, even at a high heat. 

If just enough air is blown into the fire to make 
it burn properly, all the ox^^gen will be burned 
out, and very little, if any, scale will be formed 
while heating. On the other hand, if too much 
air is used, the ox3^gen will not all be consumed 
and this unburned oxygen will attack the iron 
and form scale. This is known as "oxidizing"; 



6 FORGE-PRACTICE. 

that is, when too much air is admitted to the fire 
the surplus oxygen will attack the iron, forming 
"oxide," or scale. This sort of a fire is known as 
an "oxidizing" fire and has a tendency to "oxidize" 
anything heated in it. 

Anvil. — The ordinary anvil, Fig. i, has a body 
of cast iron, wrought iron, or soft steel, with a 
tool-steel face welded on and hardened. The 
hardened steel covers jus^ the top face, leaving 
the horn and the small block next the horn of the 
softer material. 




Fig. I. 



The anvil should be so placed that as the work- 
man faces it the horn will point toward his left. 

The square hardie-hole in the right-hand end of 
the face is to receive and hold the stems of hardies, 
swages, etc. 

For small work the anvil should weigh about 
150 lbs. 

Hot and Cold Chisels. — Two kinds of chisels are 
commonly used in the forge-shop: one for cutting 



GENERAL DESCRIPTION OF FORGE AND TOOLS. 7 

cold stock, and the other for cutting red-hot metah 
These are called cold and hot chisels. 

The cold chisel is generally made a little thicker 
in the blade than the hot chisel, which is forged 
down to a thin edge. 

Fig. 2 shows common shapes for cold and hot 
chisels, as well as a hardie, another tool used for 
cutting. 




Fig. 2. 



Both chisels should be tempered alike when 
made. 

The cold chisel holds its temper; but, from con- 
tact with hot metal, the hot chisel soon has its 
edge softened. For these reasons the two chisels 
should never be used in place of each other, for by 
using the cold chisel on hot work the temper is 
drawn and the edge left too soft for cutting cold 
metal, while the hot chisel soon becomes so soft 
that if used in place of the cold it will have its 
edge turned and ruined. 

It would seem that it is useless to temper a hot 
chisel, as the heated work, with which the chisel 



FORGE- PRACTICE. 



comes in contact, so soon draws the temper. When 
the chisel is tempered, however, the steel is left in 
a much better condition even after being affected 
by hot metal on which it is used than it would 
be if the chisel were made untempered. 

Grinding Chisels. — It is very important to have 
the chisels, particularly cold chisels, ground cor- 
rectly, and the following directions should be 
carefully followed. 

The sides of a cold chisel shoiild be ground to 
form an angle of about 60° with ^^ach other, as 
shown in Fig. 3. This makes an angle blunt 




Fig. 3. 

enough to wear well, and also sharp enough to 
cut well. 

The cutting edge should be ground convex, 
or curving outward, as at B. This prevents the 
comers from breaking off. AVhen the edge of the 
chisel is in this shape, the strain of cutting tends 
to force the corners back against the solid metal 



GENERAL DESCRIPTION OF FORGE AND TOOLS. Q 

in the central part of the tool. If the edge were 
made concave, like C, the strain would tend to 
force the corners outward and snap them off. The 
arrows on B and C indicate the direction of these 
forces. 

Hot chisels should be ground sharper. The 
sides should be ground at an angle of about 30° 
instead of 60°. 

Another tool used for cutting is the hardie. This 
takes the place of the cold or hot chisel. It has a 
stem fitted to the square hole in the right-hand end 
of the anvil face, this stem holding the hardie in 
place when in use. 

Cutting Stock. — When soft steel and wrought -iron 
bars are cut with a cold chisel the method should 
be about as follows: First cut about one-fourth 
of the way through the bar on one side; then 
make a cut across each edge at the ends of the 
first cut; turn the bar over and cut across the 
second side about one-fourth the wa}^ through; 
tilt the bar slightly, with the cut resting on the 
outside corner of the anvil, and by striking a sharp 
blow with the sledge on the projecting end, the 
piece can generally be easity broken off. 

Chisels should alwa3^s be kept carefully ground 
and sharp. 

A much easier way of cutting stock is to use 
bar shears, but these are not always at hand. 

The edge of a cJiisel should never under any circum- 
stances he driven clear through the stock and allowed 
to come in contact with the hard face of the anvil. 

Sometimes when trimming thin stock it is con- 



lO FORGE-PRACTICE. 

venient to cut clear through the piece; in this 
case the cutting should be done either on the horn, 
the soft block next the horn, or the stock to be 
cut should be backed up with some soft metal. 
An easy way to do this is to cut a wide strip of 
stock about two inches longer than the width of 
the face of the anvil, and bend the ends down to 
fit over the sides of the anvil. The cutting may 
be done on this without injury to the edge of the 
chisel. It is very convenient to have one of these 
strips always at hand for use when trimming thin 
work with a hot chisel. 

The author has seen a copper block used for 
this same purpose. The block 
was formed like Fig. 4, the stem 
being shaped to fit into the hardie- 
hole of the anvil. This block was 
designed for use principall)^ when 
Fig. 4. trimming thin parts of heated 

work with a hot chisel. 

Care should always be taken to see that the 
work rests fiat on the anvil or block when 
cutting. The work should be supported directly 
underneath the point where the cutting is to be 
done; and the solider the support, the easier the 
cutting. 

Hammers. — Various shapes and sizes of hammers 
are used, but the commonest, and most convenient 
for ordinary use, is the ball pene-hammer shown in 

Fig. 5- 

The large end is used for ordinary work, and 
the small ball end, or pene, for riveting, scarfing, 




GENERAL DESCRIPTION OF FORGE AND TOOLS. 



etc. These hammers vary in weight from a few 
ounces up to several pounds. For ordinary use 
about a i^- or 2 -pound hammer is used. 

Several other types in ordinary use are illustrated 





Fig. 5. 



Fig. 6. 



in Fig. 6, A is a straight-pene ; B, a cross-pene; 
and C, a riveting-hammer. 

Sledges. — Very light sledges are sometimes made 
the same shape as ball-pene hammers. They are 
used for light tool-work and boiler- work. 

Fig. 7 illustrates a common shape for sledges. 
This is a double-faced sledge. 







V 



A 




Fig. 7. 



Fig. 8. 



Sledges are also made with a cross-pene or straight- 
pene, as shown in Fig. 8. 



12 FORGE-PRACTTCE. 

For ordinary work a sledge should weigh about 
lo or 12 lbs.; for heavy work, from i6 to 20. 

Sledges for light work weigh about 5 or 6 lbs. 

Tongs. — Tongs are made in a wide variety of 
shapes and sizes, depending upon the work they 
are intended to hold. Three of the more ordinary 
shapes are illustrated. 

The ordinary straight- jawed tongs are shown in 
Fig. 9. They are used for holding flat iron. For 
holding round iron the jaws are grooved or bent 
to the shape of the piece to be held. 

Fig. 10 shows a pair of bolt-tongs. These tongs 
are used for holding bolts or pieces which are larger 
on the end than through the body, and are so 
shaped that the tongs do not touch the enlarged end 
when the jaws grip the body of the work. 



Fig. 9. 




Fig. 10. 




Fig. II. 



Pick-up tongs, Fig. 11, are used for handling 
small pieces, tempering, etc., but are very seldom 
used for holding work while forging. 



GENERAL DESCRIPTION OF FORGE AND TOOLS. 1 3 

Fitting Tongs to Work. — Tongs should always be 
carefully fitted to the work they are intended to 
hold. 

Tongs which fit the work in the manner shown 
in Fig. 12 should not be used until more carefully 
fitted. In the first case shown, the jaws are too 
close together; and in the second case, too far 
apart. 




Fig. 12. 



Fig. 13. 



When properly fitted, the jaws should touch 
the work the entire length, as illustrated in Fig. 
13. With properly fitted tongs the work may be 
held firmly, but if fitted as shown in Fig. 12 there 
is always a very ' ' wobbly ' ' action between the 
jaws and the work. 

To fit a pair of tongs to a piece of work, the jaws 
should be heated red-hot, the piece to be held 
placed between them, and the jaws closed down 
tight around the piece with a hammer. To pre- 
vent the handles from being brought too close 
together while the tongs are being fitted, a short 
piece of stock should be held between them just 



14 FORGE-PRACTICE. 

back of the jaws. If the handles are too far apart, 

a few blows just back of the eye will close them up. 

Flatter — Set-hammer — Swage — Fuller — Swage-block. 

— Among the commonest tools used in forge-work 
are the ones mentioned above. 

The flatter, Fig. 14, as its name implies, is used 
for flattening and smoothing straight surfaces. 

The face of the flatter is generally from 2 inches 
to 3 inches square, and should be kept perfectly 
smooth with the edges slightly rounding. 





Fig. 14. Fig. 15. 

Fig. 15 shows a set-hammer. This is used for 
finishing parts which cannot be reached with the 
flatter, up into corners, and work of that character. 
The face of this tool also should be smooth and 
flat, with the corners more or less rounded, depend- 
ing on the work it is intended to do. 

Set-hammers for small work should be about 
I or i^ inches square on the face. 

' ' Set-hammer " is a name which is sometimes 
given to almost any tool provided with a handle, 
which tool in use is held in place and struck with 
another hammer. Thus, flatters, swages, fullers, 
etc., are sometimes classed under the general name 
of set-hammers. 



GENERAL DESCRIPTION OF FORGE AND TOOLS. 



IS 



Fullers, Fig. i6, are used for finishing up filleted 
corners, forming grooves, and for numerous pur- 
poses which will be given more in detail later. 

They are made in a variety of sizes, the size 
being determined by the shape of the edge A. 
On a ^ inch fuller this edge would be a half-circle 
^ inch in diameter ; on a f inch it would be f inch 
in diameter, etc. 

Fullers are made "top" and "bottom." The 
one shown with a handle is a " top ' ' fuller, and 
the lower one in the illustration is a "bottom" 
fuller and has the stem forged to fit into the square 
hardie-hole of the anvil. This stem should be a 
loose fit in the hardie-hole. Tools of this character 
should never be used on an anvil where they fit 
so tightly that it is necessary to drive them into 
place. 

A top and bottom swage is shown in Fig. 17. 
The swages shown here are for finishing round 




Fig. 16. 



Fig. 18. 



Fig. 17. 

work; but swages are made to be used for other 
shapes as well. 



1 6 FORGE-PRACTICE. 

Swages are sized according to the shape they are 
made to fit. A i-inch round swage, for instance, 
is made to fit a circle i inch in diameter, and would 
be used for finishing work of that size. 

All of the above tools are made of low-carbon 
tool steel. 

A swage-block is shown in Fig. i8. These blocks 
are made in a variety of shapes; the illustration 
showing a common form for general use. This 
block is made of cast iron and is about 3^ inches 
thick. It has a wide range of uses and is very 
convenient for general work, where it takes the 
place of a good many special tools. 



CHAPTER II. 

WELDING. 

Welding-heat. — A piece of wrought iron or mild 
steel, when heated, as the temperature increases 
becomes softer and softer until at last a heat is 
reached at which the iron is so soft that if another 
piece of iron heated to the same point touches it, 
the two will stick together. The heat at which 
the two pieces will stick together is know^n as the 
welding-heat. If the iron is heated much beyond 
this point, it will bum. All metals cannot be welded 
(in the sense in which the term is ordinarily used). 
Some, when heated, remain very dense and retain 
almost their initial hardness until a certain heat 
is reached, when a very slight rise of temperature 
will cause them to either crumble or melt. Only 
those metals which, as the temperature is increased, 
become gradually softer, passing slowly from the 
solid to the liquid state, can be welded easily. 
Metals of this kind just before melting become 
soft and more or less pasty, and it is in this con- 
dition that they are most weldable. The greater 
the range of temperature through which the metal 
remains pasty the more easily may it be welded. 

In nearly all welding the greatest trouble is in 
heating the metal properly. The fire must be clean 

17 



1 8 FORGE-PRACTICE. 

and bright or the result will be a "dirty" heat; 
that is, small pieces of cinder and other dirt will 
stick to the metal, get in between the two pieces, 
and make a bad weld. 

Too much care cannot be used in welding ; if the 
pieces are too cold they will not stick, and no 
amount of hammering will weld them. On the 
other hand, if they are kept in the fire too long 
and heated to too high a temperature they will 
be burned, and burned iron is absolutely worthless. 

The heating must be done slowly enough to 
insure the work heating evenly all the way through. 
If heated too rapidly, the outside may be at the 
proper heat while the interior metal is much colder ; 
and, as soon as taken from the fire, this cooler 
metal on the inside and the air almost instantly 
cool the surface to be welded below the welding 
temperature, and it will be too cold to weld by 
the time any work can be done on it. 

If the pieces are properly heated (when welding 
wrought iron or mild steel), they will feel sticky 
when brought in contact. 

When welding, it is best to be sure that every- 
thing is ready before the iron is taken from the 
fire. All the tools should be so placed that they 
may be picked up without looking to see where 
they are. The face of the anvil should be perfectly 
clean, and the hammer in such a position that it 
will not be knocked out of the way when the work 
is placed on the anvil for welding. 

All the tools being in place, and the iron brought 
to the proper heat, the tongs should be held in 



WELDING. 1 9 

such a way that the pieces can be easily placed in 
position for welding without changing the grip or 
letting go of them ; then, when everything is ready, 
the blast should be shut off, the pieces taken from 
the fire, placed together on the anvil, and welded 
together with rapid blows of the hammer, welding 
(after the pieces are once stuck together) the 
thin parts first, as these are the parts which 
naturally cool the quickest. 

Burning Iron or Steel. — The statement that iron 
can be burned seems to the beginner to be rather 
exaggerated. The truth of this can, however, be 
very easily shown. If a bar of iron be heated in the 
forge and considerable blast turned on, the bar will 
grow hotter and hotter, until at last sparks will be 
seen coming from the fire. These sparks, which are 
quite unlike the ordinary ones from the fire, are 
white and seem to explode and form little white 
stars. 

These sparks are small particles of burning iron 
which have been blown upward out of the fire. 

The same sparks may be made by dropping fine 
iron-filings into a gas-flame, or by burning a piece 
of oily waste which has been used for wiping up 
iron-filings. 

If the bar of iron be taken from the fire at the 
time these sparks appear, the end of the bar will 
seem white and sparkling, with sparks, like stars 
similar to those in the fire, coming from it. If the 
heating be continued long enough, the end of the 
bar will be partly consumed, forming lumps similar 
to the "clinkers" taken from a coal fire. 



FORGE-PRACTICE. 



To burn iron two things are necessary: a high 
enough heat, and the presence of oxygen. 

As noted before, when welding, care must be 
taken not to have too much air going through the 
fire; in other words, not to have an oxidizing fire. 

If the fire is not an oxidizing one, there is not so 
much danger of injury to the iron by burning and 
the forming of scale. 

Iron which has been overheated and partially 
burned has a rough, spongy appearance and is 
brittle and crumbly. 

Use of Fluxes in Welding, — AVhen a piece of iron 
or steel is heated for welding under ordinary con- 
ditions the outside is oxidized; that is, a thin film 
of iron oxide is formed. This oxide is the black 
scale which is continually falling from heated iron 
and is formed when heated iron is brought in contact 
with the air. This oxide of iron is not fluid except 
at a very high heat, and, if allowed to stay on the 
iron, will prevent a good weld. 

When welding without a flux the iron is brought 
to a high enough heat to melt the oxide, which is 
forced from between the welding pieces by the 
blows of the hammer. 

This heat may easily be taken when welding 
ordinary iron; but when working with some ma- 
chine-steel, and particularly tool-steel, the metal 
cannot be heated to a high enough temperature 
to melt the oxide without burning the steel. 

From the above it would seem imipossible to weld 
steel, as it cannot be heated under ordinary condi- 
tions without oxidizing, but by the use of a flux 



WELDING. 21 

this difficulty may be overcome and the oxide 
mehed at a lower temperature. 

The flux (sand and borax are the most common) 
should be sprinkled on the part of the piece to be 
welded when it has reached about a yellow heat, 
and the heating continued until the metal is at a 
proper temperature to be soft enough to weld, but 
care should be taken to see that the flux covers 
the parts to be welded together. 

The flxtix has a double action; in the first place, 
as it melts it flows over the piece and forms a 
protecting covering which prevents oxidation, 
and also when raised to the proper heat dissolves 
the oxide that has already formed. 

The oxide melts at a much lower heat when 
combined with the flux than without it, and to 
melt the oxide is the principal use of the fliix. The 
metal when heated in contact with the flux becomes 
soft and "weldable" at a lower temperature than 
when without it. 

Ordinary borax contains water which causes it 
to bubble up when heated. If the heating is con- 
tinued at a high temperature, the borax melts 
and runs like water; this melted borax, when 
cooled, is called borax-glass. 

Borax for welding is sometimes fused as above 
and then powdered for use. 

Sal ammoniac mixed with borax seems to clean 
the surface better than borax alone. A flux made 
of one part of sal ammoniac and four parts borax 
works well, particularly when welding tool-steel, 
and is a little better than borax alone. 



2 2 FORGE-PRACTICE. 

Most patented welding compounds have borax 
as a basis, and are very little, if any, better 
than the ordinary mixture given above. 

The flux does not in any way stick the pieces 
together or act as a cement or glue. Its use is 
principally to help melt the oxide already formed 
and to prevent the formation of more. 

Iron filings are sometimes mixed with borax and 
used as a flux. 

When using a flux the work should always be 
scarfed the same as when no flux is used. The 
pieces can be welded, however, at a lower 
heat. 

Fagot or Pile Welding. — AVhen a large forging 
is to be made of wrought iron, small pieces of 
"scrap" iron (old horseshoes, bolts, nuts, etc.) 
are placed together in a square or rectangular 
pile on a board, bound together with Vv^ire, heated 
to welding heat in a furnace, and welded together 
into one solid lump, and the forging made from 
this. If there is not enough metal in one lump, 
several are made in this way and afterward welded 
to each other — making one large piece. This is 
known as fagot or pile welding. 

Sand is used for fluxing to a 
large extent on work of this kind. 
Sometimes a small fagot weld 
is made by laying two or more 
pieces together and welding them 
their entire length, or one piece 
may be doubled together several 
times and welded into a lump. Such a weld is 





WELDING. 23 

shown in Fig. 19, which shows the piece before 
welding and also after being welded and shaped. 

Scarfing. — In a fagot weld the pieces are not 
prepared or shaped for each other, being simply laid 
together and welded, but for most welding the 
ends of the pieces to be joined should be so shaped 
that they will fit together and form a smooth 
joint when welded. This is called scarfing. It 
is very important that the scarfing be properly 
done, as a badly shaped scarf will probably spoil 
the weld. For instance, if an attempt be made 
to weld two bars together simply by overlaxjping 
their ends, as in Fig. 20, the weld when finished 
would be something like Fig. 21. Each bar would 




Fig. 20. 



Fig. 21. 



be forged into the other and leave a small crack 
where the end came. On the other hand, if the 
ends of the bars were properly scarfed or pointed, 
they could be welded together and leave no mark — 
making a smooth joint. 

Lap-welds are sometimes made without scarf- 
ing when manufacturing many pieces alike, but 
this should not be attempted in ordinary work. 



24 FORGE-PRACTICE. 

Lap-weld Scarf. — In preparing for the lap-weld, 
the ends of the pieces to be welded should be first 
upset until they are considerably thicker than the 
rest of the bar. This is done to allow for the 
iron which burns off, or is lost by scaling, and 
also to allow for the hammering which must be 
done when welding the pieces together. To make 
a proper weld the joint should be well hammered 
together, and as this reduces the size of the iron 
at that point the pieces must be upset to allow 
for this reduction in size in order to have the weld 
the same size as the bar. 

If the ends are not upset enough in the first 
place, it requires considerable hard work to upset 
the weld after they are joined together. Too 
much upsetting does no hann, and the extra 
metal is very easily worked into shape. To be on 
the safe side it is better to upset a little more than 
is absolutely necessary — it may save considerable 
work afterwards. 

If more than one heating will be necessary to 
make a weld, the iron should be upset just that 
nuich more to allow for the extra waste due to 
the second or third heating. 

Flat Lap-weld.— The lap-weld is the weld ordinarily 
used to join fiat or round bars of iron together 
end to end. 

Following is a description of a fiat lap-weld: 
The ends of the pieces to be joined must be first 
upset. When heating for upsetting heat only tlie 
end as shown in Fig. 22, where tlie shaded part 
indicates the hotter metal. To heat this way 



WELDING. 



25 



place only the extreme end of the bar in the fire, 
so the heat will not run back too far. The end 
should be upset until it looks about like Fig. 23. 





Fig. 22. 



Fig. 23. 



When starting to shape the scarf use the round 
or pene end of the hammer. Do not strike directly 
down on the work, but let the blows come at an 
angle of about 45 degrees and in such a way as to 
force the metal back toward the base as shown in Fig. 





Fig. 24. 



Fig. 25. 



24. This drives the metal back and makes a sort of 
thick ridge at the beginning of the scarf. In 
finishing the scarf, use the fiat face of the hammer, 
and bring the piece to the very edge of the anvil, 
as in this way a hard blow may be struck without 
danger of hitting the anvil instead of the work. 
The proper position is shown in Fig. 25. 

The scarfs should be shaped as in Fig. 26, leav- 
ing them slightly convex and not concave, as 
shown in Fig. 27. 



26 ■ ' FORGE-PRACTICE. 

The reason for this is that if the scarfed ends be 
concave when the two pieces are put together, a 

c 





Fig. 26. Fig. 27. 

small pocket or hollow will be left between them, 
the scarfs touching only the edges. When the 
weld is hammered together, these edges being in 
contact will naturally weld first, closing up all 
outlet to the pocket. As the surface of the scarf 
is more or less covered with melted scale and 
other impurities, some of this will be held in the 
pocket and make a bad place in the weld. On 
the other hand, if the scarfs are convex, the metal 
will first stick in the very center of the scarf, forc- 
ing out the melted scale at the sides of the joint 
as the hammering continues. 

The length of the scarf should be about i| times 
the thickness of the bar; thus on a bar |" thick 
the scarf should be about |" long. 

The width of the end A should be slightly less 
than the width B of the bar. In welding the two 
pieces together, the first piece should be placed 
scarf side up on the anvil, and the second piece 
laid on top, scarf side down, in such a way that 
the thin edges of the second piece will lap over 
the thick ridge C on the first piece as shown in 
Fig. 28. The piece which is laid on top should 
be held by the smith doing the welding, the other 
may be handled by the helper. 



WELDING. 



27 



The helper should place his piece in position 
on the anvil first. As it is rather hard to lay the 
other piece directly on top of this and place it 
exactly in the right position, it is better to rest 
the second piece on the corner of the anvil as 




Fig. 2 



Fig. 29. 



shown at A, Fig. 29, and thus guide it into position. 
In this way the piece may be steadied and placed 
on the other in the right, position without any 
loss of time. 

When heating for a lap-weld, or for that matter 
any weld where two pieces are joined together, 
great care should be taken to bring both pieces 
to the same heat at the same time. If one piece 
heats faster than the other, it should be taken 
from the fire and allowed to cool until the other 
piece "catches up" with it. It requires some 
practice to so place the pieces in the fire that they 
will be heated uniformly and equally. The tips 
particularly must be watched, and it may be 
necessary to cool them from time to time in the 
water-bucket to prevent the extreme ends from 
burning off. 

The fire must be clean, and the heating should be 
done slowly in order to insure its being done evenly. 

Just before taking the pieces from the fire they 



28 i-orge-practice. 

should be turned scarf side down for a short tima 
to be sure that the surfaces to be joined will be hot. 
More blast should be used at the last moment 
than when starting to heat. 

The only way to know how this heating is going 
on is to take the pieces from the fire from time 
to time and look at them. The color grows lighter 
as the temperature increases, until finally, when 
the welding heat is reached, the iron will seem 
almost white. The exact heat can only be learned 
by experience; but the workman should recognize 
it after a little practice as soon as he sees it. 

To get an indication of the heat, which will help 
sometimes, watch the sparks that come from the 
fire. When the little, white, explosive sparks 
come they show that some of the iron has been 
heated hot enough to be melted off in small particles 
and is burning. This serves as a rough indication 
that the iron is somewhere near the welding heat. 
This should never be relied on entirely, as the 
condition of the fire has much to do with their 
appearance. 

Round Lap-weld.- — The round lap-weld — the weld 
used to join round bars end to end — is made in 
much the same way as the ordinary or fiat lap- 
weld. The directions given for making the fiat 
weld apply to the round lap as 
well, excepting that the scarf 
is slightly different in shape. 
The proper shape of scarf is 
' ^°' shown in Fig. 30, which gives 

the top and side views of the piece. One side is 



I> 



WELDING. \ 29 

left straight, the other three sides tapering in 
to meet it in a point. The length of the scarf 
should be about one and one-half times the 
diameter of the bar. Always be sure, particularly 
in small work, that the pieces are scarfed to a 
point, and not merely flattened out. The greatest 
difficulty with this weld is to have the points of 
the pieces well welded, as they cool very rapidly 
after leaving the fire. The first blows, after stick- 
ing the pieces together, should cover the points. 
The weld should be made square at first and then 
rounded. The weld is not so apt to split while 
being hammered if welded square and then worked 
round, as it would be if hammered round at first. 

If the scarf were made wide on the end like 
the ordinary lap-weld, it would be necessary to 
hammer clear around the bar in order to close 
down the weld; but with the pointed scarf, one 
blow on each point will stick the work in place, 
making it much more quickly handled. 

Ring Weld, Round Stock. A ring formed from 
round stock may be made in two ways; that is, 
by scarfing before or after bending into shape. 
When scarfed before bending, the length of stock 
should be carefully calculated, a small amount 

Fig. 31. 

being added for welding, and the ends upset and 
scarfed exactly the same as for a round lap-weld. 



3° 



FORGE PRACTICE. 



Care should be taken to see that the scarfs come 
on opposite sides of the piece. 

Fig. 31 shows a piece of stock scarfed ready for 
bending. 

After scarfing, the piece should be bent into 

a ring and welded, care 
being taken when bend- 
ing to see that the points 
of the scarf lie as indi- 
cated at A, Fig. 32, and 
not as shown at B. 

When the points of 
the scarfs are lapped as 
shown at A, most of the 
welding may be done 
while the ring lies flat on 
the anvil, the shaping 
being finished over the 
Fig. 32. horn. If the points are 

lapped the other way, B, the welding also must 
be done over the horn, making it much more awk- 
ward to handle. 

The second way of welding the ring is practically 
the same as that of making a chain link, and the 
same description of scarfing will answer for both, 
the stock being cut and bent into a ring, with the 
ends a little distance apart; these ends are then 
scarfed the same as described below for a link 
scarf and welded in exactly the same manner 
as described for making the other ring. 

Chain-making. — The first step in making a link 
is to bend the iron into a U-shaped piece, being 




WELDING. 31 

careful to keep the legs of the U exactly even in 
length. The piece should be gripped at the lower 
end of the U, the two ends brought to a high heat, 
scarfed, bent into shape together, reheated, and 
welded. 

To scarf the piece place one end of the U on the 
anvil, as shown in Fig. t,t,, and strike one blow on 
it ; move it a short distance in the direction shown 
by the arrow and strike another blow. This 
should be continued until the edge or comer of 
the piece is reached, moving it after each blow. 



^ 



Fig. 33. Fig. 34. 

This operation leaves a series of little steps on 
the end of the piece, and works it out in a more 
or less pointed shape, as shown in Fig. 34. 

This scarf may be finished by being brought 
more to a point by a few blows over the horn of 
the anvil. The ends should then be bent together 
and welded. Fig. 35 shows the steps in making 
the link and two views of the finished link. The 
link is sometimes left slightly thicker through 
the weld. A second link is made — all but welding — 
spread open, and the first link put on it, closed 
up again, and welded, A third is joined to this 
etc. 

When made on a commercial scale, the links are 



32 



PORGE-PRACTICE. 



not scarfed but bent together and welded in one 
heat. 




Fig. 35. 
Ring, or Band. — A method of making a ring from 




^ 



^> 



Fig. 36. 

flat iron is shown in Fig. 36, which shows the 
stock before and after bending into shape. 



WELDING. S3 

The stock is cut to the correct length, upset, 
and scarfed exactly the same as for a flat lap-weld. 
The piece is bent into shape and welded over the 
horn of the anvil. The ring must be heated for 
welding very carefully or the outside lap will 
bum before the inside is hot enough to weld. 

In scarfing this — as in making other rings — care 
must be taken to have the scarfs come on opposite 
sides of the tock. 

Washer, or Flat Ring. — In this weld flat stock 
is used bent edgewise into a ring without any 
preparation. The corners of the ends are trimmed 
off parallel after the stock is bent as shown in 
Fig- 37. 





Fig. 37, Fig. 38. 

After trimming the ends are scarfed with a 
fuller or pene end of a hammer and lapped ready 
for welding (Fig. 38). 

When heating for welding, the ring should be 
turned over several times to insure uniformity in 
heating. 

If the work is particular, the ends of the stock 
should be upset somewhat before bending into 
shape. 



34 rORGE-PRACTICE. 

Butt-weld. — This is a weld where the pieces 
are butted together without any slanting scarfs, 
leaving a square joint through the weld. 

When two pieces are so welded the ends should 
be slightly rounded, simillar to Fig. 39, which 
shows two pieces ready for welding. If the ends 
are convex as shown, the scale and other impurity 
sticking to the metal is forced out of the joint. 
If the ends were concave this matter would be 



Fig. 39. Fig. 40. 

held between the pieces and make a poor weld. 
The pieces are welded by being struck on the ends 
and driven together. This, of course, upsets the 
metal near the weld and leaves the piece something 
like Fig. 40, showing a slight seam where the 
rounded edges of the ends join. This upset part 
is worked down to size at a welding heat, leaving 
the bar smooth. 

A butt-weld is not as safe or as strong as a lap- 
weld. 

When the pieces are long enough they may be 
welded right in the fire. This is done by placing 
the pieces in the fire in the proper position for 
welding; a heavy weight is held against the pro- 
jecting end of one piece — to "back it up" — and 
the weld is made by driving the pieces together 
by hammering on the projecting end of the second 
piece. As soon as the work is "stuck," the weld 




WELDING. 3 5 

is taken from the fire and finished on the 
anvil. 

Jump Weld. — Another form of butt-weld, Fig. 41, 
is the "jump" weld, which, 
however, is a form which should 
be avoided as much as possible, 
as it is very liable to be weak. 
When making a weld like this, the 
piece which is to be "jumped," 
or "butted," on to the other ^^'^- 41 • 

piece should have its end upset in such a way as 
to flare out and form a sort of flange the wider 
the better. When the weld is made, this flange — 
indicated by the arrow — can be welded down with a 
hammer, or set-hammers, and make a fairly strong 
weld. 

Split Weld; Weld for very Thin Steel. — Very thin 
stock is sometimes difficult to join with the ordi- 
nary lap-weld for the reason that the stock is so 
thin that if the pieces are taken from the fire at the 
proper heat they will be too cold to weld before 
they can be properly placed together on the anvil. 

This difficulty is somewhat overcome by scarfing 
the ends, similar to Fig. 42. The ends are tapered 




Fig. 42- 

to a blunt edge and split down the center for half an 
inch or so, depending on the thickness of stock. 
One half of each split end is bent up, the other 



36 



FORGE-PRACTICE. 



down; the ends are pushed tightly together and 
the spHt parts closed down on each other, as shown 




Fig. 43- 

in Fig. 43. The joint may then be heated and 
welded. 

This is a weld sometimes used for welding spring 
steel, or iron to steel. 

Split Weld; Heavier Stock. — A split weld for 
heavier stock is shown ready for welding in Fig. 




Fig. 44. 




Fig. 45- 





Fig. 46. 

45, Fig. 44 showing the two pieces before they are 
put together. In this weld the ends of the pieces 
are first upset and then scarfed, one piece being 



WELDING. 37 

split and shaped into a Y, while" the other has its 
end brought to a point with the sides of the bar 
just back of the point bulging out slightly as shown 
at A and B. This bulge is to prevent the two 
pieces from slipping apart. 

When properly shaped the two pieces are driven 
together and the sides, or lips, of the Y-shaped 
scarf closed down over the pointed end of the other 
piece. The lips of the Y should be long enough to 
lap over the bulge on the end of the other piece 
and thus prevent the two pieces from slipping apart. 
The pieces are then heated and welded. Care must 
be taken to heat slowly, that the pointed part may 
be brought to a welding heat without burning the 
outside piece. Borax, sand, or some other flux 
should be used. (Sometimes the faces of the scarfs 
are roughened or notched with a chisel, as shown in 
Fig. 46, to prevent the pieces from slipping apart.) 

This is the weld that is often used when welding 
tool-steel to iron or mild steel. 

Sometimes the pieces are heated separately to a 
welding heat before being placed together. Good 
results may be obtained this way when tool-steel is 
welded to iron or mild steel, as the tool-steel welds 
at a much lower temperature than either wrought 
iron or mild steel, and if the two pieces are heated 
separately, the other metal may be raised to a much 
higher temperature than the tool-steel. 

Angle Weld. — In all welding it should be remem- 
bered that the object of scarfing is to so shape the 
pieces to be welded that they will fit together and 
form a smooth joint when properly hammered. 



38 



FORGE-PRACTICE. 



Frequently there are several equally good methods 
of scarfing for the same sort of weld, and it should 
be remembered that the method given here is not 
necessarily the only way in which the particular 
weld can be made. 

Fig. 47 shows one way of 
scarfing for a right-angle weld 
made of flat iron. Both pieces 
are scarfed exactly alike. The 
scarfing is done with the pene 
end of the hammer. If neces- 
sary the ends of the pieces 
may be upset before scarfing. 

As in all other welds, care 
must be taken to so shape the 
scarfs that when they are placed 
together they will touch in the 
center, and not around the edges, thus leaving an 
opening for forcing out the impurities which collect 
on the surfaces to be welded. 




Fig. 47- 




Fig. 48. 
"T" Weld. — A method of scarfing for a "T" 
weld is illustrated in Fig. 48, 



WELDING. 



3V 



The stem, A, should be placed on the bar, B, 
when welding in about the position shown by the 
dotted line on B. 

"T" Weld, Round Stock. — Two methods of 
scarfing for a " f " weld made from round stock are 
shown in Fig. 49. 




Fig. 49. 



The scarfs are formed mostly with the pene end 
of the hammer. 

The illustration will explain itself. The stock 
should be well upset in either method. 

Welding Tool - steel. — The general method of 
scarfing is the same in all welding ; but when tool- 
steel is to be welded, either to itself or to wrought 
iron or mild steel, more care must be used in the 
heating than when working with the softer metals 
alone. 

The proper heat for welding tool-steel — about a 
bright yellow — can only be learned by experiment. 
If the tool-steel is heated until the sparks fly, a 
light blow of the hammer will cause it te crumble 
and fall to pieces.. 



40 FORGE-PRACTICE. 

When welding mild steel or wrought iron to tool- 
steel, the tool-steel should be at a lower heat than 
the other metal, which should be heated to its reg- 
ular welding heat. 

The flux used should be a mixture of about one 
part sal ammoniac and four parts borax. 

Tool-steel of high carbon, and such as is used for 
files, small lathe tools, etc., can seldom be welded to 
itself in a satisfactory manner. What appears to 
be a first-class weld may be made, and the steel 
may work up into shape and seem perfect — ^may, in 
fact, be machined and finished without showing 
any signs of the weld — ^but when the work is hard- 
ened, the weld is almost certain to crack open. 

Spring steel, a lower carbon steel, may be satis- 
factorily welded if great care be used. 



CHAPTER III. 

CALCULATION OF STOCK FOR BENT SHAPES. 

Calculating for Angles and Simple Bends. — It is 

often necessary to cut the stock for a forging as 
nearly as possible to the exact length needed. This 
length can generally be easily obtained by meas- 
ment or calculation. 

About the simplest case for calculation is a plain 
right-angle bend, of which the piece in Fig. 50 will 
serve as an example. 

This piece as shown is a simple right-angle bend 
made from stock 1" through, 8" long on the outside 
of each leg. 



^ 



Fig. 50. 



t 







^ 


\ K— 8= » 



Fig. 51. 



Suppose this to be made of wood in place of iron. 
It is easily seen that a piece of stock 1" thick and 
15" long would make the angle by cutting off 7" 

41 



42 rORGE-PRACTICE. 

from one end and fastening this piece to the end of 
the 8" piece, as shown in Fig. 51. 

This is practically what is done when the angle is 
made of iron — only, in place of cutting and fasten- 
ing, the bar is bent and hammered into shape. 

In other words, any method which will give the 
length of stock required to make a shape of uniform 
section in wood, if no allowance is made for cutting 
or waste, will also give the length required to make 
the same shape with iron. 

An easier way — which will serve for calculating 
lengths of all bent shapes — is to measure the length 
of an imaginary line drawn through the center of 
the stock. Thus, if a dotted line should be drawn 
through the center of stock in Fig. 50, the length of 
each leg of this line would be 7^", and the length of 
stock required 15", as found before. 

No matter what the shape when the stock is left 
of uniform width through its length, this length of 
straight stock may always be found by measuring 
the length of the center line on the bent shape. 
This may be clearly shown by the following experi- 
ment. 

Experiment to Determine Part of Stock which 
Remains Constant in Length while Bending. — Sup- 
pose a straight bar of iron with square ends be 
taken and bent into the shape shown in Fig. 52. If 

the length of the bar be 
measured on the inside 
edge of the bend and then 
^^^- 52. on the outside, it will be 

found that the inside length is considerably shorter 




CALCULATION OF STOCK FOR BENT SHAPES 43 

than the outside; and not only this, but the inside 
will be shorter than the original bar, while the out- 
side will be longer. The metal must therefore 
squeeze together or upset on the inside and 
stretch or draw out on the outside. If this is the 
case, as it is, there must be some part of the bar 
which when it is bent neither squeezes together nor 
draws out, but retains its original length, and this 
part of the bar lies almost exactly in the center, as 
shown by the dotted line. It is on this line of the 
bent bar that the measuring must be done in order 
to determine the original length of the straight 
stock, for this is the only part of the stock which 
remains unaltered in length when the bar is bent. 

To make the explanation a little clearer, suppose 
a bar of iron is taken, polished on one side, and lines 
scratched upon the surface, as shown in the lower 
drawing of Fig. 53, and this bar then bent into the 
shape shown in the upper drawing. Now if the 
length of each one of these lines be measured and 
the measurements compared with the length of the 
same lines before the bar was bent, it would be 
found that the line A A, on the outside of the bar, 
had lengthened considerably; the line BB would 
be somewhat lengthened, but not as much as A A; 
and CC would be lengthened less than BB. The 
line 00, through the center of the bar, would meas- 
ure almost exactly the same as when the bar was 
straight. The line DD would be found to be 
shorter than 00 and FF shorter than any other. 
The line 00, at the center of the bar, does not 
change its length when the bar is bent; conse- 



44 



FORGE-PRACTICE. 



quently, to determine the length of straight stock 
required to bend into any shape, measure the 



-5^- 







Fig. 53. 



Fig. 54. 



length of the line following the center of the stock 
of the bent shape. 

As another example Fig. 54 will serve. 

Suppose a center line be drawn, as shown by the 
dotted line. As the stock is i" thick, the length of 
the center line of the part A will be 5'^ at B 8'', 
C 5", D 2", E 2,^", and the total length of stock 
required 2I^'^ 

A convenient form for making calculations is as 
follows : 



Total , 



A- 


= 5" 


B- 


= 8" 


C- 


= 5" 


E- 


=3r 




2ir 



length of stock required. 



Curves. Circles. Methods of Measuring. — On cir- 
cles and curves there are several different methods 
which may be employed in determining the length 
of stock, but the same principle must be followed 



CALCULATION OF STOCK FOR BENT SHAPES. 45 

in any case — the length must be measured along 
the center line of the stock. 

One way of measuring is to lay off the work full size. 
On this full-size drawing lay a string or thin, easily 
bent wire in such a way that it follows the shape 
of the bend through its entire length, being careful 
that the string is laid along the center of the stock. 

The string or wire may then be straightened and 
the length measured directly. 

Irregular shapes or scrolls are easily measured in 
this way. 

Another method of measuring stock for scrolls, 
etc., is to step around a scroll with a pair of dividers 
with the points a short distance apart, and then lay 
off the same number of spaces in a straight line and 
measure the length of that line. This is of more 
use in the drawing-room than in the shop. 

Measuring-wheel. — -Still another way of measuring 
directly from the drawing is to use a 
light measuring-wheel, similar to 
the one shown in Fig. 55, mounted 
in some sort of a handle. This is a 
thin light wheel generally made 
with a circumference of about 
24". The side of the rim is some- 
times graduated in inches by 
eighths. To use it, the wheel is 
placed lightly in contact with the 
line or object which it is wished 
to measure, with the zero-mark on ^'°- 55- 

the wheel corresponding to the point from which 
the measurement is started. The wheel is then 




46 FOKGE-PRACTICE. 

pushed along the surface following the line to be 
measured, with just pressure enough to make it 
revolve. By counting the revolutions made and 
setting the pointer or making a mark on the wheel 
to correspond to the end of the line when it is 
reached, it is an easy matter to push the wheel over 
a straight line for the same number of revolutions 
and part of a revolution as shown by the pointer 
and measure the length. If the wheel is gradu- 
ated, the length run over can of course be read 
directly from the figures on the side of the wheel. 

Calculating Stock for Circles. — On circles and parts 
of circles, the length may be calculated mathe- 
matically, and in the majority of cases this is prob- 
ably the easiest and most accurate method. This 
is done in the following way: The circumference, or 
distance around a circle, is equal to the diameter 
multiplied by 3I (or more accurately, 3. 141 6). 

As an illustration, the length of stock required to 
bend up the ring in Fig. 56 is calculated as follows: 
The inside diameter of the ring is 6" and the 
stock 1" in diameter. The length must, of course, 
be measured along the center 
of the stock, as shown by 
the dotted line. It is the 
diameter of this circle, made 
by the dotted line, that is 
used for calculating the 
length of stock; and for 
convenience this may be 
Fig. 56. called the "calculating" di- 

ameter, shown by C in Fig. 56. 




CALCULATION OF STOCK FOR BENT SHAPES. 47 

The length of this calculating diameter is equal 
to the inside diameter of the ring with one-half the 
thickness of stock added at each end, and in this 
case would be i" + 6" + i" = 7". 

The length of stock required to make the ring 
would be 7"X3|-=22"; or, in other words, to find 
the length of stock required to make a ring, multi- 
ply the diameter of the ring, measured from center 
to center of the stock, by 3^. 

Calculating Stock for " U's." — Some shapes may 
be divided up into straight lines and parts of circles 
and then easily calculated. Thus u — 3y2 — J 
the U shape in Fig. 57 may be ''~ 
divided into two straight sides and 
a half -circle end. The end is half of 
a circle having an outside diameter 
of 3^ . The calculating diameter of 
this circle would be 3", and the 
length of stock required for an entire Fig. 57. 

circle this size 3X3^ = 9!, which for convenience 
we may call 9f ", as this is near enough for ordinary 
work. As the forging calls for only half a circle, 
the length needed would be 9f"-^2 = 4itt"- 

As the circle is 3^' outside diameter, half of this 
diameter, or if", must be taken from the total 
length of the U to give the length of the straight 
part of the sides ; in other words, the distance from 
the line A to the extreme end of the U is half the 
diameter of the circle, or if". This leaves the 
straight sides each 4^" long, or a total length for 
both of 8^". The total stock required for the 
forging would be : 




48 



FORGE-PRACTICE. 



Total 



Length stock for sides 8^" 

" " end 4I1'' 

" " " forging i3-,V'. 




Link. — As another example, take the link shown 
In Fig. 58. This may be divided into the two semi- 
circles at the ends and the 
two straight sides. Calcu- 
lating as always through 
the center of the stock, 
there are the two straight 
sides 2" long, or 4'^ and the 
■^^^- 58- two semicircular ends, or 

one complete circle for the two ends. The length 
required for these two ends would be 1^X3^'' = 
ff" = 4i", or, nearly enough, 4}^''. The total length 
of the stock would be 4'^ + 4||" = 8i|^'"', to which 
must be added a slight amount for the weld. 

Double Link. — The double link in Fig. 59 is an- 
other example of stock calculation. Here there 
are two complete circles each hav- 
ing an inside diameter of f, and, 
as they are made of \" stock, a 
"calculating^' diameter of 1" . The 
length of stock required for one side 
would be 3. 1 41 6" X i" = 3. 141 6", 
and the total length for complete 
links 3.i4i6"X 2" = 6.2832", which is about 6Y': 

As a general rule it is much easier to make the 
calculations with decimals as above and then 
reduce these decimals to eighths, sixteenths, etc. 




Fig. 59. 



CALCULATION OF STOCK FOR BENT SHAPES. 49 

Use of Tables- — To aid in reduction a table of 
decimal equivalents is given on p. 249. By using 
this table it is only necessary to find the decimal 
result and select the nearest sixteenth in the table. 
It is generally sufficiently accurate to take the 
nearest sixteenth-. 

A table of circumferences of circles is also given; 
and by looking up the diameter of any circle the 
circumference may be found opposite. 

To illustrate, suppose it is necessary to find the 
amount of stock required to make a ring 6" inside 
diameter out of |" round stock. This would make 
the calculating diameter of the ring 6f . 

In the table of circimiferences and areas of circles 
opposite a diameter 6f is found the circumference 
21.206. In the table of decimal equivalents it will 
be seen that -A- is the nearest sixteenth to the deci- 

1 b 

mal .206; thus the amount of stock required is 
2i-^^Q-". This of' course makes no allowance for 
welding. 

Allowance for Welding. — Some allowance must 
always be made for welding, but the exact amount 
is very hard to determine, as it depends on how 
carefully the iron is heated and how many heats 
are taken to make the weld. 

The only stock which is really lost in welding, 
and consequently the only waste which has to be 
allowed for, is the amount which is burned off or 
lost in scale when heating the iron. 

Of course when preparing for the weld the ends 
of the piece are upset and the work consequently 
shortened, and the pieces are still farther shortened 



50 FORGE-PRACTICE, 

by overlapping the ends in making the weld; but 
all this material is afterward hammered back into 
shape so that no loss occurs here at all, except of 
course the loss from scaling. 

A skilled workman requires a very small allow- 
ance for waste in welding, in fact sometimes none 
at all; but by the beginners an allowance should 
always be made. 

No rules can be given; but as a rough guide on 
small work, a length of stock equal to from one- 
fourth to three-fourths the thickness of the bar will 
probably be about right for waste on rings, etc. 
When making straight welds, when possible it is 
better to allow a little more than is necessary and 
trim off the extra stock from the end of the finished 
piece. 

Work of this kind should be watched very closely 
and the stock measured before and after welding in 
order to determine exactly how much stock is lost 
in welding. In this way an accurate knowledge is 
soon obtained of the proper allowance for waste. 



CHAPTER IV. 

UPSETTING, DRAWING OUT, AND BENDING. 

Drawing Out. — When a piece of metal is worked 
out, either by pounding or otherwise, in such a way 
that the length is increased, and either the width or 
thickness reduced, we say that the metal is being 
" drawn out," and the operation is known as " draw- 
ing out." 

It is always best when drawing out to heat the 
metal to as high a heat as it will stand without 
injury. Work can sometimes be drawn out much 
faster by working over the horn of the anvil than on 
the face, the reason being this: when a piece of 
iron is laid fiat on the anvil face and hit a blow w4th 
the hammer, it flattens out and spreads both length- 
wise and crosswise, making the piece longer and 
wider. The piece is not wanted wider, however, 
but only longer, so it is necessary to turn it on edge 
and strike it in this position, when it will again in- 
crease in length and also in thickness, and will have 
to be thinned out again. A good deal of work thus 
goes to either increasing the width or thickness, 
which is not wanted increased; consequently this 
work and the work required to again thin the forg- 
ing are lost. In other words, wlien drawing out 
iron on the face of the anvil the force of the blow is 

51 



52 



rORGE-PRACTICE. 



expended in forcing the iron sidewise as well as 
lengthwise, and the work used in forcing the iron 
sidewise is lost. Thus only about one half the 
force of the blow is really used to do the work 
wanted. 

Suppose the iron be placed on the horn of the 




Fig. 6o. 



anvil, as shown in Fig. 60, and hit with the hammef 
as before. The iron will still spread out sidewise a 
little, but not nearly as much as before and will 
lengthen out very much more. The horn in this 
case acts as sort of a blunt wedge, forcing out the 
metal in the direction of the arrow, and the force of 
the blow is used almost entirely in lengthening the 
work. 

Fullers may be used for the same purpose, and 
the work held either on the horn or the face of the 
anvil. 

Drawing Out and Pointing Round Stock. — When 
drawing out or pointing round stock it should always 
be first forged down square to the required size and 
then, in as few blows as possible, rounded up. 

Fig. 61 illustrates the different steps in drawing 
out round iron to a smaller size, A is the original 



UPSETTING, DRAWING OUT, AND BENDING. 



53 



bar, B is the first step, C is the next, when the iron 
is forged octagonal, and the last step is shown at D, 




Fig. 6i. 

where the iron is finished up round. In drawing 
out a piece of round iron it should first be forged 
like B, then like C, and lastly finished like D. 

As an example: Suppose part of a bar of f" 
round stock is to be drawn down to |" in diameter. 
Instead of pounding it down round and round until 
the I" diameter is reached, the part to be drawn out 
should be forged perfectly square and this drawn 
down to I", keeping it as nearly square as possible 
all the time. 

The corners of the square are forged off, making 
an octagon, and, last of all, the work is rounded up. 
This prevents the metal from splitting, as it is very 
liable to do if worked round and round. 




Fig. 62. 



Fig. 63. 



The reason for the above is as follows : Suppose 
Fig. 62 represents the cross-section of a round bar 



54 FORGE-PRACTICE. 

as it is being hit on the upper side. The arrows 
indicate the flow of the metal — that is, it is forged 
together at AA and apart at BB. Now, as the bar 
is turned and the hammering continued, the out- 
side metal is forced away from the center, which 
may, at last, give way and form a crack; and by 
the time the bar is of the required size, if cut, it 
would probably look something like Fig. 63. 

The same precaution must be taken when forging 
any shaped stock down to a round or conical point. 
The point must first be made square and then 
rounded up by the method given above. If this is 
not done the point is almost sure to split. 

Squaring Up Work. — A common difficulty met 
with in all drawing out, or in fact in all work which 
must be hammered up square, is the liability of the 
bar to forge into a diamond shape, or to have one 
corner projecting out too far. If a section be cut 
through a bar misshaped in this way, at right angles 
to its length, instead of being a square or rectangle, 
the shape will appear something like one of the out- 
lines in Fig. 64. 




Fig. 65. 

To remedy this and square up the bad corners, 
lay the bar across the anvil and strike upon the 
projecting corners as shown in Fig. 65, striking in 
such a way as to force the extra metal back into the 



UPSETTING, DRAWING OUT, AND BENDING. 55 

body of the bar, gradually squaring it off. Just as 
the hammer strikes the metal it should be given a 
sort of a sliding motion, as indicated by the arrow. 

No attempt should be made to square up a corner 
of this kind by simply striking squarely down upon 
the work. The hammering should all be done in 
such a way as to force the metal back into the bar 
and away from the corner. 

Upsetting. — When a piece of metal is worked in 
such a way that its length is shortened, and either 
or both its thickness and width increased, the piece 
is said to be upset; and the operation is known as 
upsetting. 

There are several ways of upsetting, the method 
depending mostly on the shape the work is in. With 
short pieces the work is generally stood on end on 
the anvil and the blow struck directly on the upper 
end. The work should always be kept straight; 
after a few blows it will probably start to bend and 
must then be straightened before more upsetting is 
done. 

If one part only of a piece is to be upset, then the 
heat must be confined to that part, as the part of 
the work which is hottest will be upset the most. 

When upsetting a short piece for its entire length, 
it will sometimes work up like Fig. 66. This may 
be due to two causes: either the ends were hotter 
than the center or the blows of the hammer were 
too light. To bring a piece of this sort to uniform 
size throughout, it should be heated to a higher heat 
in the center and upset with heavy blows. If the 
work is very short it is not always convenient to 



56 FORGE-PRACTICE. 

confine the heat to the central part ; in such a case, 
the piece may be heated all over, seized by the tongs 
in the middle and the ends cooled, one at a time, in 
the water-bucket. 



Fig. 66. Fig. 67. 

When light blows are used the effect of the blow 
does not reach the middle of the work, and conse- 
quently the upsetting is only done on the ends. 

The effect of good heating and heavy blows is 
shown in Fig. 67. With a heavy blow the work is 
upset more in the middle and less on the ends. 
• To bring a piece of this kind to uniform size 
throughout, one end should be heated and upset 
and then the other end treated in the same way, 
confining the heat each time as much as possible 
to the ends. 

Long work may be upset by laying it across the 
face of the anvil, letting the heated end extend two 
or three inches over the edge, the upsetting being 
done by striking against this end with the hammer 
or sledge. If the work is heavy the weight will 
offer enough resistance to the blow to prevent the 
piece from sliding back too far at each blow; but 
with lighter pieces it may be necessary to "back 
up" the work by holding a sledge against the un- 
heated end. 



UPSETTING, DRAWING OUT, AND BENDING. 57 

Another way of upsetting the ends of a heavy 
piece is to " ram ' ' the heated end against the side of 
the anvil by swinging the work back and forth hori- 
zontally and striking it against the side of the anvil. 
The weight of the piece in this case takes the place 
of the hammer and does the upsetting. 

Heavy pieces are sometimes upset by lifting them 
up and dropping or driving them down on the face 
of the anvil or against a heavy block of iron resting 
on the floor. Heavy cast-iron plates are sometimes 
set in the floor for this purpose, and are called 
* ' upsetting-plates . ' ' 

Fig. 68 shows the effect of the blows when upset- 
ting the end of a bar. The lower piece has been 
properly heated and upset with 
heavy blows, while the other 
piece shows the effect of light 
blows. This last shape may also 
be caused by having the extreme 
end at a higher heat than the rest 
of the part to be upset. ^^^- ^^■ 

Punching. — There are two kinds of punches used 
for making holes in hot metal — the straight hand- 
punch, used with a hand-hammer, and the punch 
made from heavier stock and provided with a 
handle, used with a sledge-hammer. 

Punches should, of course, be made of tool-steel. 

For punching small holes in thin iron a hand- 
punch is ordinarily used. This is simply a bar of 
round or octagonal steel, eight or ten inches long, 
with the end forged down tapering, and the extreme 
end the same shape, but slightly smaller than the 




58 



FORGE-PRACTICE. 



hole which is to be punched. Such a punch is 
shown in Fig. 69. The punch should taper uni- 
formly, and the extreme end should be perfectly 
square across, not in the least rounding. 



c^ 




Fig. 69. 



Fig. 70. 



For heavier and faster work with a helper, a 
punch like Fig. 70 is used. This is driven into the 
work with a sledge-hammer. 

A, B, and C, in Fig. 71, show the different steps 
in punching a clean hole through a piece of hot iron. 




Fig. 71. 

The punch is first driven about half-way through 
the bar while the work is lying fiat on the anvil ; 
this compresses the metal directly underneath the 
punch and raises a slight bulge on the opposite side 
of the bar by which the hole can be readily located. 
The piece is then turned over and the punching 
completed from this side, the small piece, "A", 
being driven completely through. This leaves a 



UPSETTING, DRAWING OUT, AND BENDING. 59 

clean hole ; while if the punching were all done from 
one side, a burr, or projection, would be raised on 
the side where the punch came through. 

D and E (Fig. 71) illustrate the effects of proper 
and improper punching. If started from one side 
and finished from the other the hole will be clean 
and sharp on both sides of the work; but if the 
punching is done from one side only a burr will be 
raised, as shown at E, on the side opposite to that 
from which the punching is done. 

If the piece is thick the punch should be started, 
then a little powdered coal put in the hole, and the 
punching continued. The coal prevents the punch 
from sticking as much as it would without it. 

Bending. — Bends may be roughly divided into two 
<:lasses — curves and angles. 

Angles. — In bending angles it is nearly always 
necessary to make the bend at some definite point 
on the stock. As the measurements are much easier 
made while the stock is cold than when hot, it is 
best to "lay off" the stock before heating. 

The point at which the bend is to be made should 
be marked with a center punch — generally on the 
edge of the stock, in preference to the side. 

Marking with a cold chisel should not be done 
unless done very lightly on the edge of stock. If a 
slight nick be made on the side of a piece of stock to 
be bent, and the stockbent at this point with the 
nick outside, the small nick will expand and leave 
quite a crack. If the nick be on the inside, it is apt 
to start a bad cold shut which may extend nearly 
through the stock before the bending is finished. 



6o 



FORGE-PRACTICE. 



Whenever convenient, it is generally easier to 
bend in a vise, as the piece may be gripped at the 
exact point where the bend is wanted. 

When making a bend over the anvil the stock 
should be laid flat on the face, with the point at 







Fig. 72. 

which the bend is wanted almost, but not quite, up 
to the outside edge of the anvil. 

The bar should be held down firmly on the anvil 
by bearing down on it with a sledge, so placed that 
the outside edge of the sledge is about in line with 
the outside edge of the anvil. 

This makes it possible to make a short bend with 
less hammering than when the sledge is not used. 

The bar will pull over the edge of the anvil 
slightly when bending. 

Bend with Forged Comer. — Brackets and other 
forgings are sometimes made with 
the outside corner of the bend 
forged up square, as shown in 

Fig. 73- 

There are several ways of 
bending a piece to finish in this 
Fig. 73. shape. 

One way is to take stock of the required finished 



./ 



UPSETTING, DRAWING OUT^ AND BENDING. 6 1 

size and bend the angle, forging the corner square 
as it is bent ; another is to start with stock consid- 
erably thicker than the finished forging and draw 
down both ends to the required finished thickness, 
leaving a thin-pointed ridge across the bar at the 
point where the bend will come, this ridge forming 
the outside or square corner of the angle where the 
piece is bent ; or this ridge may be formed by upset- 
ting before bending. 

The process in detail of the first method men- 
tioned is as follows : The first step is to bend the bar 
so that it forms nearly a right angle, keeping the 
bend as sharp as possible, as shown at A (Fig. 74). 




Fig. 74. 

This should be done at a high heat, as the higher 
the heat the easier it is to bend the iron and conse- 
quently the sharper the .bend. 

Working the iron at a good high heat, as before, 
the outside of the bend should be forged into a 
sharp corner, letting the blows come in such a way 
as to force the metal out where it is wanted, being 
careful not to let the angle bend so that it becomes 
less than a right angle or even equal to one. Fig. 



62 FORGE-PRACTICE. 

74. 5, shows the proper ^yay to strike. The arrows 
indicate the direction of the blows. 

The A\-ork should rest on top of the anvil while 
this is being done, not over one comer. If worked 
over the corner, the stock will be hammered too 
thin. 

The object in keeping the angle obtuse is this: 
The metal at the comer of the bend is really being 
upset, and the action is somewhat as follows: In 
Fig. 75 is sho-UTL the bent piece on the anvil. We 
will suppose the blows come on the part .4 in the 
direction indicated by the hea^w arrow. The 
metal, being heated to a high soft heat at C, upsets, 
part of it forming the sharp outside comer and 
part flowing as sho^Ti by the small arrow at C and 




Fig. 76 



making a sort of fillet on the inside comer. If in 
place of ha^^Lng the angle greater than 90 degrees it 
had been an acute angle (Fig. 76), the metal forced 
do'\ATiward by the blows on A would carr}^ with it 
part of the metal on the inside of the piece B, and 
a cold shut or crack would be formed on the inside 
of the angle. To form a soiuid bend the comer 
must be forged at an angle greater than a right 
angle. When the piece has been brought to a sharp 



UPSETTING, DRAWING OUT, AND BENDING. 



63 




Fig. 77. 



corner the last step is to square up the bend over 
the corner, or edge, of the anvih 

The second way of making the above is to forge 
a piece as shown in Fig. 77, 
where the dotted hnes indi- 
cate the size of the original 
piece. This piece is then 
bent in such a way that the 
ridge, C, forms the outside 
sharp corner of the angle. 

This ridge is sometimes upset in place of being 
drawn out. 

The first method described is the most satisfac- 
tory. 

Ring-bending. — In making a ring the first step 
of course is to calculate and cut from the bar the 
proper amount of stock. The bend should always 
be started from the end of the piece. For ordinary 
rings up to 4" or 5" in diameter the stock should 
be heated for about one-half its length. To start 
bending, the extreme end of the piece should be 
first bent over the horn of the anvil, and the bar 
should be fed across the horn of the anvil and bent 
down as it is pushed forward. Do 
not strike directly on top of the 
horn, but let the blows fall a little 
way from it, as in Fig. 78. This 
bends the iron and does not pound 
it out of shape. One-half of the 
ring is bent in this way and then the part left 
straight is heated. This half is bent up the same 
as the other, starting from the end exactly as before. 




Fig. 78. 



64 



FORGE-PRACTICE. 




— The first step in niaking an eye 

like Fig. 79 is to calculate the 

amount of stock required for the 

bend. The amount required in this 

case, found by looking up the circum- 

FiG. 79. ference of a 2" circle in the table, is 

7 V'. This distance should be laid off by making 

a chalk-mark on the face of the anvil 7 V' from the 

left-hand end. 

A piece of iron is heated and laid on the anvil with 
the heated end on the chalk-mark, the rest of the 
bar extending to the left. A hand-hanmier is held 
on the bar with the edge of the hammer directly in 
line with the end of the anvil. This measures ofT 
7^' from the edge of the hammer to the end of the 
bar. The bar is then laid across the anvil bringing 
the edge of the hammer exactly in line with the 
outside edge of the anvil, thus leaving 7^'' project- 
ing over the edge. This projecting end is bent 
down until it forms a right angle. The extreme 
end of this bent part is then bent over the horn into 



1st 



^AC 



2nd 



3rd 




4th 




Fig. So. 



the circular shape and the bending continued until 
the eye is formed. 



UPSETTING, DRAWING OUT, AND BENDING. 



65 



The same general method as described for bend- 
ing rings should be followed. The different steps 
are shown in Fig. 80. 

If an eye is too small to close 
up around the horn, it may be 
closed as far as possible in 
this way, and then completely 
closed over the corner or on 
the face of the anvil, as shown 
in Fig. 81. 

Double Link. — Another good ^^<^- ^^■ 

example of this sort of bending is the double link, 
shown in Fig. 59. 

The link is started by bending the stock in the 
exact center, the first step being to bend a right 
angle. This step, with the succeeding ones, is 
shown in Fig. 82. 




1st C 



3rd 



2nd 





Fig. 82. 



After this piece has been bent into a right angle, 
the ring on the end should be bent in the same way 



66 FORGE-PRACTICE. 

as an ordinary ring ; excepting that all the bending 
is done from one end of the piece, starting from the 
extreme end as usual. 

Twisting. — Fig. 83 shows the effects produced by 
twisting stock of various shapes — square, octagonal, 




. Fig. 83. 

and flat, the shapes being shown by the cuts in 
each case. 

To twist work in this way it should be brought to 
a uniform heat through the length intended to 
twist. When the bar is properly heated it should 
be firmly gripped with a pair of tongs, or in a vise, 
at the exact point where the twist is to commence. 
With another pair of tongs the work is taken hold 
of where the twist is to stop, and the bar twisted 
through as many turns as required. The metal 
will of course be twisted only between the two pairs 
of tongs, or between the vise and the tongs, as the 
case may be; so care must be used in taking hold 
of the bar or the twist will be made at the wrong 
points. 

The heat must be the same throughout the part 
to be twisted. If one part is hotter than another, 



UPSETTING, DRAWING OUT, AND BENDING. 



67 



this hotter part, being softer, will twist more easily, 
and the twist will not be uniform. If one end of 
the bar is wanted more tightly twisted than the 
other, the heat should be so regulated that the part 
is heated hottest that is wanted tightest twisted; 
the heat gradually shading off into the parts wanted 
more loosely twisted. 

Reverse Twisting. — The effect shown in Fig. 84 
is produced by reversing the direction of twisting. 




Fig. 84. 



A square bar is heated and twisted enough to 
give the desired angle. It is then cooled, in as 
sharp a line as possible, as far as B, and twisted 
back in the opposite direction. It is again heated, 
cooled up to A, and twisted in the first direction; 
and this operation is continued until the twist is of 
the desired length. 



CHAPTER V. 

SIMPLE FORGED WORK. 

Twisted Gate-hook. — This description answers, of 
course, not only for this particular piece, but for 
others of a like nature. 

Fig. 85 shows the hook to be made. To start 
with, it must be determined what length of stock, 



> K 




Fig. 85. 

after it is forged to proper size, will be required to 
bend up the ends. 

The length of straight stock necessary should, of 
course, be measured through the center of the 
stock on the dotted lines in the figure. To do this 
lay out the work full size, and lay a string or thin 
piece of soft wire upon the lines to be measured. 
It is then a very easy matter to straighten out the 
wire or string, and measure the exact length re- 
quired. If the drawing is not made full size, an 
accurate sketch may be made on a board, or other 
flat surface, and the length measured from this. 



SIMPLE FORGED WORK. 69 

The hook as above will require about 2|" length 
for stock; the eye, about 2|". 
The first step would be like Fig. 86. 



H 2%----^{^ i 4 -^« H 

Fig. 86. 

After cutting the piece of .,\" square stock, start 
the forging by drawing out the end, starting from 
the end and working back into the stock until a 
piece is forged out 2\" long and \" in diameter. 
Now work in the shoulder with the set-hammer in 
the following way: 

Forming Shoulders: Both Sides — One Side. — Place 
the piece on the anvil in such a position that 
the point where the shoulder is wanted comes 
exactly on the nearest edge of the anvil. Place 
the set -hammer on top of the piece in such a way 
that its edge comes directly in line with the edge of 
the anvil (Fig. 87). Do not place the piece like 



O — ' — O 



Fig 87. Fig 88. 

Fig. 88, or the result will be as shown — a shoulder 
on one side only. As the shoulder is worked in the 
piece should be turned continually, or the shoulder 




70 FORGE-PRACTICE. 

will work in faster on one side than on the other. 
Always be careful to keep the shoulder exactly even 
with the edge of the anvil. 

When the piece is formed in the proper shape on 
one end, start the second shoulder 4" from the first, 
and finish like Fig. 86. Bend the eye and then the 
hook; and, lastly, put the twist in the center. 
Make the twist as follows: 

First make a chalk-mark on the jaws of the vise, 

so that when the end of the hook is even with the 

mark the edge of the vise will be where one end of 

the twist should come. Heat the part to be twisted 

to an even yellow heat (be sure 

that it is heated evenly) ; place 

it in a vise quickly, with the end 

even with the mark; grasp the 

piece with the tongs, leaving the 

p g distance between the tongs and 

vise equal to the length of twist 

(Fig. 89) ; and twist it aroimd one complete turn. 

The eye should be bent as described before, and 
the hook bent in the same general way as the eye. 

Grab-hooks. — This is the name given to a kind 
of hooks used on chains, and made for grabbing or 
hooking over the chain. The hook is so shaped that 
the throat, or opening, is large enough to slip eas- 
ily over a link turned edgewise, but too narrow to 
slip down off this link on to the next one, which, of 
course, passes through the first link at right angles 
to it. 

Grab-hooks are made in a variety of ways, one of 
vhich is given below in detail. 



SIMPLE FORGED WORK. 7 1 

Fig. 90 will serve as an example. To forge this, 
use a bar of round iron large enough in section to 
form the heavy part of the hook. This bar should 
first be sHghtly upset, either by ramming or ham- 
mering, for a short distance from the end, and then 
flattened out like Fig. 91. 





Fig. 90. Fig. 92. Fig. 93. 

The next step is to round up the part for the e3^e, 
as shown in Fig. 92, by forming it over the comer of 
the anvil as indicated in Fig. 93. The eye should 
be forged as nearly round as possible, and then 
punched. 

Particular attention should be paid to this point. 
If the eye is not properly rounded before punching, 
it is difficult to correct the shape afterward. 

After punching, the inside comers of the hole are 
rounded off over the horn of the anvil in the man- 
ner shown in Fig. 94. Fig. 95 shows the appear- 
ance of a section of the eye as left by the punch. 
When the eye is finished it should appear as though 
bent up from round iron — that is, all the square 
corners should be rounded off as shown in Fig. 96. 

When the eye is completed the bodv of the hook 



72 



FORGE-PRACTICE. 



should be drawn out straight, forged to size, and 
then bent into shape. Care should be taken to 





Fig. 94. 



Fig. 95. Fig. 96. 




keep the hook thickest around the bottom of the 
bend. 

As the stock is entirely formed before bending, 
the length of the straight piece must be carefully 

measured, as indicated 
at A (Fig. 97), where 
the piece is shown ready 
^^' ^'^' for bending. To deter- 

mine the required length the drawing or sample 
should be measured with a string or piece of flexible 
wire, measuring along the center of the stock, from 
the extreme point to the center of the eye. 

The weakest point of almost any hook is in the 
bottom bend. When the hook is strained there is 
a tendency for it to straighten out and take the 
shape shown by the dotted lines in Fig. 90. To 
avoid this the bottom of the hook must be kept as 
thick as possible along the line of strain, which is 
shown by the line drawn through the eye. A good 
shape for this lower bend is shown in the sketch, 
where it will be noticed that the bar has been ham- 
mered a little thinner in ordfr to increase the thick- 
ness of the metal in the direction of the line of 
strain. 



SIMPLE FORGED WORK. 73 

The part of the hook most hable to bend under a 
load is the part lying between the points marked 
Zand /in Fig. 102. 

Another style of grab-hook is shown in Fig. 98, 




Fig. 98. 

which shows the finished hook and also the straight 
piece ready for bending. 

The forming will need no particular description. 
The hook shown is forged about |" thick; the out- 
side edge around the curve being thinned out to 
about I", in order to give greater stiffness in the 
direction of the strain. 

Stock about |" X i" is used. 

A very convenient way to start the eye for a hook 
of this kind, or in fact almost any forged eye, is 
shown in Fig. 99. Two fullers, top and bottom, 
arc used, and the work shaped as shown. The bar 
should be turned, edge for edge, between every few 
blows, if the grooves are wanted of the same depth. 
After cutting the grooves the edge is shaped the 
same as described above. 

A grab-hook, sometimes used on logging-chains, 
is shown in Fig. 100. This is forged from square 



74 FORGE-PRACTICE. 

stock by flattening and forming one end into an eye 
and pointing the other end; after which the hook 
is bent into shape. 





Fig. 99. Fig. 100. 

Welded Eye-hooks. — Hooks sometimes have the 

eye made by welding instead of forging from the 

soUd stock. Such a hook is shown in Fig. 10 1, 




Fig. ioi. 

which also shows the stock scarfed and bent into 
shape ready for closing up the eye for the weld, and 
also the eye ready for welding. Before heating for 
the weld, the eye should be closed, and stock at the 
end be bent close together. The scarf should be 
pointed the same as for any other round weld. 



SIMPLE FORGED WORK. 



75 



This sort of eye is not as strong as a forged eye 
of the same size ; but is usually as strong as the rest 
of the hook, as the eye is generally considerably 
stronger than any other part. 

Hoisting-hooks. — A widely accepted shape for 
hoisting-hooks, used on 
cranes, etc., is shown in 
Fig. 1 02. The shape and 
formula are given by Henry 
R. Town, in his Treatise on 
Cranes. 

r = working load in tons 
of 2000 lbs. 

A = diameter of round 
stock used to form hook. 

The size of stock to use 
for a hook to carry any 
particular load is given below. The capacity of 
the hook, in tons, is given in the upper line — the 
figures in the lower line, directly under any particu- 
lar load in the upper line, giving the size of bar 
required to form a hook to be used at that load. 




Fig. 



^ = 1 H 



1 1 

4 2 

1 



r 1 

'IS 



4568 



2i 2 + 



10 

3i 



The other dimensions of the hook are found by 
the following formula, all the dimensions being in 
inches : 

D= .57 +1.25 

E= .647"+ 1.6 

F= .33T+ .85 



76 FORGE-PRACTICE. 

G^ .7SD 
0= .3637+ .66 
Q= .647+1.6 
H=i.oSA 

J=1.2A 

K=i.i3A 
L=i.osA 
M= .sA 
Ar= .85S-.16 
U= .866A 

To illustrate the use of the table, suppose a hook 
is wanted to raise a load of 500 lbs. 

In the line marked T in the table are found the 
figures \, denoting a load of one-quarter of a ton, or 
500 lbs. Under this are the figures ||, giving the 
size stock required to shape the hook. 

The different dimensions of the hook would be 
found as follows : 

£=.64x74 + 1-6" = 1.76 = 17/' about. ■ 

/f=i.o8A = i.o8X"/i3=.74 =7^ about. 
^= I -33^4 = 1.33X^716= -91 5 = '732 about. 

When reducing the decimals, the dimensions 
which have to do only with the bending of the hook, 
that is, the opening, the length, the length of point, 
etc., may be taken as the nearest i6th, but these 
dimensions for flattening should be reduced to the 
nearest 3 2d on small hooks. 



SIMPLE FORGED WORK. 77 

The complete dimensions for the hook— m--ques- 
tion, I coo lbs. capacity, would be as follows : 



D=iv:' 


G=i" 


H=y:' 


L=-/3/' 


E=iv:' 


0= v/' 


r_29/ /t 

^ /32 


M=-/3/' 


F= 'VJ' 


Q=l3//' 


J = 'VJ' 








i^-'/a/' 


t/=Vi/' 



Bolts. — Bolts are made by two methods, upset- 
ting and welding. The first method is the more 
common, particularly on small bolts, where it is 
nearly always used, the stock being upset to 
form the head. In the second method the head is 
formed by welding a ring of stock around the stem. 

An upset head is stronger than a welded head, 
provided they are both equally well made. 
• The size of the bolt is always given as the diame- 
ter and length of the shank, or stem. Thus, a 
\" bolt, 6" long, means a bolt having a shank \" in 
diameter, and 6" long from the under side of the 
head to the end. 

Dimensions of bolt-heads are determined from 
the diameter of the shank, and should always be 
the same size for the same diameter, being inde- 
pendent of the length. 

The diameter and thickness of the head are meas- 
ured as shown in Fig. 103. 

The dimensions of both square and hexagonal 
heads are as follows: 

D = diameter of head across the flats (short 
diameter) . 

T = thickness of head. 

5 = diameter of shank of bolt. 



78 



FORGE- PRACTICE. 



For a 2" bolt the dimensions would be calcu- 
lated as follows : 

Diameter of head would equal iV'X2" + ^" = 

0/8 • 

Thickness of head would be 2". 

These are dimensions for rough or unfinished 
heads; each dimension of a finished head is V^/'' 
less than the same dimension of the rou8:h head. 




m 



W 



\y 



Fig. 



Bolts generally have the top comers of the head 
rounded or chamfered off (Fig. 103). This can 
be done with a hand-hammer, or with a cupping- 




C^, 



C 




Fig. 104. Fig. 105. 

tool (Fig. 104), which is simply a set-hammer with 
the bottom face hollowed out into a bowl or cup 
shape. 



SIMPLE FORGED WORK. 79 

For making bolts one special tool is required, 
the heading-tool. This is commonly made some- 
thing the shape of Fig. 105, although for a "hurry- 
up" bolt sometimes any flat strip of iron with a 
hole punched the proper size to admit the stem of 
the bolt can be used. 

When in use this tool is placed on the anvil 
directly over the square hardie-hole, the stem of 
the bolt projecting down through the heading-tool 
and hardie-hole while the head is being forged on 
the bolt. 

This heading-tool is made with one side of the 
head flush with the handle, the other side project- 
ing a quarter of an inch or so above it. The tool 
should always be used with the flat side on the anvil. 

Upset-head Bolt. — An upset head is made as fol- 
lows : The stock is first heated to a high heat for a 
short distance at the end, and upset as shown at 
Fig. 106. The bolt is then dropped a 
through the heading tool, the up- 
set portion projecting above. This 
upset part is then flattened down 
on the tool as shown at B, and 
forged square or hexagonal on the 
anvil. Fig. 106. 

The hole in the heading-tool should be large 
enough to allow the stock to slip through it nearly 
up to the upset portion. 

Welded-head Bolts. — A welded-head bolt is made 
by welding a ring of square iron around the shank 
to form the head, which is then shaped in a heading- 
tool the same as an upset head. A piece of square 



8o 



rORGE-PRACTICE. 



iron of the proper size is bent into a ring, hut not 
welded. About the easiest way to do this is to take 
a bar several feet long, bend the ring on the end, and 
then cut it off as shown in Fig. 107. 




\^ 



Fig. 107. 



This ring is just large enough, when the ends are 
slightly separated, to slip easily over the shank. 

The shank is heated to about a welding heat, the 
ring being slightly cooler, and the two put together 
as sho^^^l in Fig. 107, B. The head is heated and 
welded, and then shaped as described above. 

When welding on the head it should be hammered 
square the first thing, and not pounded round and 
round. ^ It is much easier to make a sound weld by 
forging square. 

Care must be used when taking the welding heat 
to heat slowly, otherwise the outside of the ring will 
be burned before the shank is hot enough to stick. 

It is sometimes necessary when heating the bolt- 
head for welding to cool the outside ring to prevent 
its burning before the shank has been heated suffi- 
ciently to weld ; to do this put the bolt in the water 



SIMPLE FORGED WORK. 



8l 



oideways just far enough to cool the outside edge of 
the ring and leave the central part, or shank, hot. 

Tongs. — Tongs are made in a great variety of 
ways, several of which are given below. 

Common flat- jaw tongs, such as are used for 
holding stock up to about f inch thick, may be 
made as follows: Stock about | inch square 
should be used. This is first bent like A, Fig. 
io8. To form the eye the bent stock is laid 




Fig. ioS 



across the anvil in the position shown at B, and 
flattened by striking with a sledge the edge of the 
anvil, forming the shoulder for the jaw. A set- 
hamxner may be used to do this by placing the 
piece with the other side up, flat on the face of the 
anvil, and holding the set-hammer in such a way as 
to form the shoulder with the edge of the hammer, 
the face of the hammer flattening the eye. 



82 FORGE-PRACTICE. 

The long handle is drawn out with a sledge, 
working as shown at C. When drawing out work 
this way the forging should always be held with 
the straight side up, the comer of the anvil forming 
the sharp comer up against the shoulder on the 
piece. If the piece be turned the other side up, 
there is danger of striking the projecting shoulder 
with the sledge and knocking the work out of shape. 

For finishing up into the shoulder a set-hammer 
or swage should be used, and the handles should 
be smoothed off with a flatter, or between top and 
bottom swages. The jaw may be flattened as 
shown aXD. 

The inside face of the jaw should be slightly 
creased with a fuller, as this insures the tongs grip- 
ping the work firmly with the sides of the jaws, and 
not simply touching it at one point in the center, as 
they sometimes do if this crease is not made. 

After the tongs have been shaped, and are fin- 
ished in every other way, the hole for the rivet 
should be punched. The rivet should drop easily 
into the hole. The straight end of the rivet should 
be brought to a high heat, the two parts of the 
tongs placed together with the holes in line, the 
rivet inserted, and the end "headed up." Most of 
the heading should be done with the pene end of 
the hammer. After riveting the tongs will prob- 
ably be rather ' ' stiff ' ' ; opening and shutting them 
several times, while the rivet is still red-hot, will 
leave them loose. The tongs should be finished 
by fitting to a piece of stock of the size on which 
thev are to be used. 



SIMPLE FORGED WORK. 



83 



Light Tongs. — Tongs may be made from, flat stock 
in the following way : A cut is made with a narrow 
fuller at the right distance from the end of the bar 
to leave enough stock to form the jaw between the 
cut and the end, as shown at A, Fig. 109. 




Fig. 109. 

This end is bent over as shown at B and a second 
fuller cut made, shown at C, to form the eye. The 
other end of the bar is drawn out to form the handle, 
as indicated by the dotted lines. The jaw is shaped, 
the rivet-hole punched, and the tongs finished, as 
at D, in the usual way. 

Tongs of this character may be used on light 
work. 

Tongs for Round Stock. — Tongs for holding 
round stock may be made by either of the above 
methods, the operations 
in making being the 
same, with the exception 
of shaping the jaws, 
which may be done in 
this way: A top fuller 
and bottom swage are Fig. ho. 

used, the swage being of the size to which it is 
wished to finish the outside of the jaws, the fuller 




84 



FORGE-PRACTICE. 



the size of the inside. The jaw is held on the swage, 
and the fuller placed on top and driven down on 
it, Fig. no, forcing the jaw to take the desired 
shape, shown at A. The final fitting is done as 
usual, after the jaws are riveted together. 

Welded Tongs. — Tongs with welded handles are 
made in exactly the same way as those with solid, 
drawn-out handles excepting that, in place of draw- 
ing out the entire length of the handle, a short stub 
only is forged, a few inches long, and to this is 
welded a bar of round stock to form the handle. 
Fig. Ill shows one ready for welding. 



n> <n:^^>^ 



Fig. III. 

Pick-up Tongs. — No particular description is 
necessary for making pick-up tongs. The tongs 
may be drawn out of a fiat piece and bent as 
shown in Fig. 112. 



A. 



V 



Fig. 112. 



Bolt-tongs. — Bolt-tongs are easily made from 
round stock, although square may be used to 
advantage. 

The first operation is to bend the bar in the shape 



SIMPLE FORGED WORK. 



85 



shown in Fig. 113. This may be done with a fuller 
over the edge of the anvil, as shown at A. When 
bending the extreme end of the jaw the bar should 
be held almost level at first, and gradually swung 
down, as shown by the arrow, until the end is prop- 
erly bent. 





Fig. 113. 



Fig. 114. 



The eye may be flattened with the set-hammer, 
and the part between the jaw proper and the eye 
worked down to shape over the horn and on the 
anvil with the same tool. 

The jaw proper is rounded and finished with a 
fuller and swage, as shown in Fig. 114. 

There is generally a tendency for the spring of 
the jaw to open up too much in forging. This 
may be bent back into shape either on the face of 
the anvil, as shown at A (Fig. 115), or over the 
horn, as at B. 

Another method of making the first bend, when 
starting the tongs, is shown in Fig. 116. A swage- 
block and fuller are here used; a swage of the 



86 



FORGE-PRACTICE. 



proper size could of course be used in place of the 
block. 





Fig. 115. 



Fig. 116. 



Ladle. — A ladle, similar to Fig. 117, may be 
made of two pieces welded together, one piece 
forming the handle, the other the bowl. 

A square piece of stock of the proper thickness 
is cut and "laid out" (or marked out) like Fig. 
118; the center of the piece being first found by 
drawing the diagonals. 




Fig. 117 



A circle is drawn as large as possible, with its 
center on the intersection of the diagonals; the 
piece is cut out with a cold chisel to the circle, 
excepting at the points where projections are left 
for lips and for a place to weld on the handle. This 
latter projection is scarfed and welded to the strip 
forming the handle. 



SIMPLE FORGED WORK. 



87 



The bowl is formed from the circular part by 
heating it carefully to an even yellow heat and 
placing it over a round hole in a swage-block or 
other object. The pene end of the hammer is used, 
and the pounding done over the hole in the swage- 
block. As the metal in the center is forced down- 
ward by the blow of the hammer, the swage-block 
prevents the material at the sides from following 
and is gradually worked into a bowl shape. 

Fig. 119 shows the position of the block and the 
piece when forging. 

The bowl being shaped properly, the lips should 
be fonned, and the top of the bowl ground off true. 





Ftg. 119. 



Fig. 120. 



The lips may be formed by holding the part 
where the lips are to be against one of the smaller 
grooves in the side of the swage-block, and driving 
it into the groove by placing a small piece of round 
iron on the inside of the bowl as shown in Fig. 120. 

For a ladle with a bowl 3^' in diameter, the diam- 
eter of the circle, cut from the flat stock, should be 
about 4", as the edges of the piece draw in some- 
v/hat. Stock for other sizes should be in about 
the same proportion. Stock should be about \" 
thick. 



FORGE-PRACTICE. 







Fig. 



Machine-steel should be used for • making the 
bowl. If ordinary wrought iron is used, the metal 
is liable to split. 

Bowls. — Bowls, and objects of similar shape, 
may be made in the manner described above, but 
care must be used not to do too much hammering in 
the center of the stock, as that is the part most 
liable to be worked too thin. 

Chain-stop. — The chain-stop, shown in Fig. 121, 
will serve as an example of a very numerous class 

of forgings; that is, forg- 
ings having a compara- 
tively large projection 
^ on one side. 

Care should be taken 
to select stock, for pieces 
of this sort, that will work into the proper shape with 
the least effort. The stock should be as thick as 
the thickest part of the forging, 
and as wide as the widest part. 
Stock, in this particular case, 
should be Y'Xii"- 

The different steps in making 
the forging are shown in Fig. 
122. First two cuts are made 
lY^ apart, as shown at A ; then 
these cuts are widened out with 
a fuller, B. The ends are then 
forged out square, as at C. To 
finish the piece the hole is F^^. 122. 

punched and rounded and the ends finished 
round. 




SIMPLE FORGED WORK. 



89 



When the fuller is used it should be held 
slightly slanting, as shown in 
Fig. 123. 

This forces the metal toward 
the central part and leaves a 
more nearly square shoulder, in 
place of the slanting shoulder 
that would be left were the fuller to be held exactly 
upright. 




Fig. 123. 



CHAPTER VI. 

CALCULATION OF STOCK; AND MAKING OP 
GENERAL FORCINGS. 

Stock Calculations for Forged Work. — When cal- 
culating the amount of stock required to make a 
forging, when the stock has its original shape 
altered, there is one simple rule to follow: Calcu- 
late the volume of the forging, add an allowance 
for stock lost in forging, and cut a length of stock 
having the total volume. In other words, the 
forging contains the same amount, or volume, of 
metal, no matter in what shape it may be, as the 
original stock ; an allowance of course being made 




-iW- 



-55^ 



Fig. 124. 

for the slight loss by scaling, and for the parts cut 

off in making. 

Take as an example the forging shown in Fig. 

124, to determine the amount of stock required to 

90 



CALCULATION OF STOCK; GENERAL FORCINGS. 9 1 

make the piece. This forging could be made in 
much the same way as the chain-stop. A piece of 
straight stock would be used and two cuts made 
and widened with a fuller, in the manner shown 
in Fig. 125. The ends on either side of the cuts 



'dU 



XJ L£ 



Fig. 125. 



are then drawn down to size, as shown by the 
dotted lines, the center being left the size of the 
original bar. The stock should be ^" X i", as these 
are the dimensions of the largest parts of the forg- 
ing. For con\enience in calculating the forging 
may be divided into three parts: the round end 
A, the central rectangular block B, and the square 
end C. 

The block B will of course require just 2" of 
stock. 

The end C has a volume of yx^"X3"=|- of a 
cubic inch. 

The stock (yxi") has a volume of V'Xi" 
X i" =^ of a cubic inch for each inch of length. 

To find the number of inches of stock required to 
make the end C, the volume of this end (f cubic 
inch) should be divided by the volume of one inch 
of stock (or ^- cubic inch). Thus, 1^1 = i^". 

It will therefore requi^'e iV' of stock to make 
the end C; with allowance for scaling, if". 

The end A is really a round shaft, or cylinder, 
4." long and ^" in diameter. To find the volume 



92 FORGE-PRACTICE. 

of a cylinder, multiply the square of half the diame- 
ter by-3V7, and then multiply this result by the 
length of the cylinder. 

The volume of .4 would be V, X V, X 3 V; X 4 = ^ V14. 
And the amount of stock required to make A would 
be "/14 -^ V2=' I V7" i^ length, which is practically 
equal to lYg. To the above amount of stock must 
be added a small amount for scaling, allowing alto- 
gether about i^//'. 

The stock needed for the different parts of the 
forging is as follows : 

Round shaft A if" 

Block B 2" 

Square shaft C if" 



Total s^ 



// 



First taking a piece of stock i"Xi"X5f", the 
cuts would be made for drawing out the ends as 
shown in Fig. 125. 

In such a case as the above it is not always neces- 
sary to know the exact amount of stock to cut. 
What is known to be more than enough stock to 
make the forging could be taken, the central block 
made the proper dimensions, the extra metal 
worked down into the ends, and then trimmed off 
to the proper length. There are frequently times, 
however, when the amount of material required 
must be calculated accurately. 

Take a case like the forging shown in Fig. 126. 
Here is what amounts to two blocks, each 2^X4" 
X6", connected by a round shaft, 2" in diameter. 



CALCULATION OF STOCK; GENERAL FORCINGS. 



93 



To make this, stock 2" thick and 4" wide should 
be used, starting by making cuts as shown in Fig. 



Sip- 






Fig. 126. 



127, and drawing down the center to 2" round. 
It is of course necessary to know how far apart to 



^ 



&> 



T 



i^ L 






FlG. 127. 

make the cuts when starting to draw down the 
center. 

The volume of a cylinder 2" in diameter and 
24" long would be i" X i" X3 'A" X24" = 75 V^ cubic 
inches, which maybe taken as 75 Yj cubic inches. 
For each inch in length the stock would have a 
volume of 4"X2"Xi"=8 cubic inches. There- 
fore it would require 75^/2"^^ =9 Vie inches of stock 
to form the central piece; consequently the dis- 
tance between cuts, shown at A in Fig. 127, would 
have to be qVio"- Each end would require 6" of 
stock, so the total stock necessary would be 

Any forging can generally be separated into sev- 
eral simple parts of uniform shape, as was done 
above, and in this form the calculation^ can be 



94 rORGE-PRACTICE. 

easily made, if it is always remembered that the 
amount of metal remains the same, and in forging, 
merely the shape, and not the volume, is altered. 

Weight of Forgings.^To find the weight of any 
forging, the volume may first be found in cubic 
inches, and this volume multiplied by .2779, the 
weight of wrought iron per cubic inch. (If the 
forging is made of steel, multiply by .2836 in place 
of .2779.) This will give the weight in pounds. 

Below is given the weight of both wrought and 
cast iron and steel, both in pounds per cubic inch 
and per cubic foot. 

Lbs. per Lbs. per 

Cu. Ft. Cu, In. 

Cast iron weighs.. 450 .2604 

Wrought iron weighs. . 480 -2779 

Steel weighs 490 -2936 

Suppose it is required to find the weight of the 
forging shown in Fig. 124. We had a volume in 
A of ^y 14 cubic inch, in C of ^/^ cubic inch, and in 
5 of I cubic inch, making a total of 2 ^^/^^ cubic 
inches. If the forging were made of wrought iron, 
it would weight 2^V28><-2 779 =-7 oi a pound. 

The forging shown in Fig. 126 has a volume in 
each end of 48 cubic inches, and in the center of 
75f cubic inches, making a total of i7iy cubic 
inches, and would weigh, if made of wrought iron, 
47.64 pounds. 

A much quicker way to calculate weights is to 
use a table such as is given on page 250. As steel 
is now commonly used for making forgings, this 



CALCULATION OF STOCK; GENERAL FORGINGS 95 

table is figured for steel. The weight given in the 
table is for a bar of steel of the dimensions named 
and one foot long. Thus a bar i" square weighs 
3.402 lbs. per foot, a bar 3i"Xi" weighs 11.9 lbs. 
per foot, etc. 

To calculate the weight of the forging shown in 
Fig. 126, proceed as follows; Each end is 2^X4" 
and 6" long, so, as far as weight is concerned, equal 
to a bar 4"X2" and 12" long. From the table, 
a bar 4"Xi" weighs 13.6 lbs. for each foot in 
length; so a bar 4"X2", being twice as thick, 
would weigh twice as much, or 27.2 lbs., and as 
the combined length of the two ends of the forging 
is one foot, this would be their weight. The table 
shows that a bar 2" in diameter weighs 10.69 ^bs. 
for every foot in length; consequently the central 
part of the forging, being 2 ft. long, would weigh 
10.69X2, or 21.38 lbs. The total weight of the 
entire forging would be 48.58 lbs. (This seems to 
show a difference between this weight and the 
weight as calculated before, but it must be remem- 
bered that before the weight was calculated for 
wrought iron, while this calculation was made for 
steel.) 

Finish. — Some forgings are machined, or "fin- 
ished," after leaving the forge-shop. As the draw- 
ings are always made to represent the finished 
work, and give the finished dimensions, it is neces- 
sary to make an allowance for this finishing when 
making the forging, and all parts which have to 
be "finished," or "machined," must be left with 
extra metal to be removed in finishingr. 



96 



FORGE-PRACTICE. 



The parts required to be finished are generally 
marked on the drawing; sometimes the finished 
surfaces have the word finish marked on them; 
sometimes the finishing is shown simply by the 
symbol /, as used in Fig. 128, showing that the 
shafts and pin only of the crank are to be finished. 



— /- 






Fig. i2{ 



When all surfaces of a piece are to be finished 
the words finish-all-over are sometimes marked 
on the drawing. 

The allowance for finish on small forgings is gen- 
erally about Yie" on each surface ; thus if a block 
were wanted to finish 4"X2"Xi", and Vie" were 
allowed for finishing, the dimensions of the forging 

should be 4Y'X2i''Xir- 

On a forging like Fig. 126, about ^" allowance 
should be made for finish, if it were called for; 
thus the diameter of the central shaft would be 
2i", the thickness of the ends 2^", etc. On larger 
work Y' is sometimes allowed for machining. 

The amount of finish allowed depends to a large 
extent on the way the forging is to be finished. If 
it is necessary to finish by filing the forging should 
be made as nearly to size as possible, and having 
a very slight amount for finisii, Vg/', or even ^/^i", 
being enough in some cases. 



CALCULATION OF STOCK) GENERAL FORCINGS. 



97 



It is of course necessary to take this into account 
when calculating stock, and the calculation made 
for the forging with the allowance for finish added 
to the drawing dimensions and not simply for the 
finished piece. 

Crank-shafts. — There are several methods of 
forging crank-shafts, but only the common com- 
mercial method will be given here. 

When forgings were mostly made of wrought iron, 
cranks were welded up of several pieces. One 
piece was used for each of the end shafts, one piece 
for each cheek, or side, and another piece for the 
crank-pin. Mild-steel cranks are now more uni- 
versally used and forged from one solid piece of 
stock. The drawing for such a crank is given in 
Fig. 128; finish to be allowed only as shown, that 
is, only on crank-pin and shafts. The forgings, as 
made, will appear like the outlines in Fig. 129. 
The metal in the throat of the crank is generally 
removed by drilling a line of holes and then sawing 
slots where the sides of the crank cheeks should 
come, as shown by the dotted lines in Fig. 129. 



-8^- 



r 



-+>/- 



Fig. 129. 



The central block is then easily knocked out. This 
drilling and sawing are done in the machine-shop. 
This throat can be formed by chopping out the 



98 



FORGE-PRACTICE. 



surplus metal with a hot chisel, but on small cranks, 
such as here shown, it is generally cheaper in a well- 
equipped shop to use the first method. 

The first step is to calculate the amount of stock 
required. Stock i^"X4" should be used. The 
ends, A and B, should be left i^" in diameter to 
allow for finishing. The end A contains 10.13 
cubic inches. Each inch of stock contains 6 cubic 
inches. It would therefore require 1.7" of stock 
to form this end provided there were no waste from 
scale in heating. This waste does take place, and 
must be allowed for, so it will be safe to take about 
2" of stock for this end. B contains 5.22 cubic 
inches, and would require .87" of stock without 
allowance for scale. About i-|" should be taken. 
The stock should then be 7!" long. The first step 
is to make cuts i^^" from one end and 2" from the 
other, and widen out these cuts with a fuller, as 
shown in Fig. 130. 





Fig. 130. 



Fig. 131. 



These ends are then forged out round in the man- 
ner illustrated in Fig. 131. The forging should be 
placed over the corner of the anvil in the position 
shown, the blows striking upon the corner of the 
piece as indicated. As the end gradually straightens 



CALCULATION OF STOCK; GENERAL FORCINGS. 



99 



out, the other end of the piece is slowly raised into 
the position shown by the dotted lines and the 
shaft hammered down round and finished up be- 
tween swages. 

Care must be taken to spread the cuts properly 
before drawing down the ends, otherwise a bad 
cold-shut will be formed. If 
the cuts are left without spread- 
ing, the metal will act some- 
what after the manner shown 
in Fig. 132. The top part of 
the bar, as it is worked down, 
will gradually fold over, leav- 
ing, when hammered down to Fig. 132. 
size, a bad cold-shut, or crack, such as illustrated 
in Fig. 132. When the metal starts to act this way, 
as shown by the upper sketch in 132, the fault may 
be remedied by trimming off the corner along the 
dotted line. This must always be done as soon as 
any tendency to double over is detected. 

Double-throw Cranks. — Multiple-throw cranks are 



/ 



J 



-BS 



I3B- 



Fig. 133 



first forged flat, rough turned, then heated and 
twisted into shape. 

The double-throw crank, shown in Fig. 133, 



lOO FORGE-PRACTICE. 

would be first forged as shown in Fig. 134 ; the parts 
shown dotted would then be cut out with the drill 
and saw, as described above. 

After the pins and shafts have been rough turned 
— that is, turned round, but left as large as possi- 



B A 
Fig. 134. 

ble — the crank is returned to the forge-shop, where 
it is heated red-hot and twisted into the finished 
shape. 

When twisting, the crank is gripped just to one 
side of the central bearing, as shown by the dotted 
line A. This may be done with a vise or wrench, 
if the crank is small, or the crank may be placed 
on the anvil of a steam-hammer and the hammer 
lowered down on it to hold it in place. 

The other end of the crank is gripped on the line 
B and twisted into the required shape. 




Fig. 135. 



A wrench of the shape shown in Fig. 135 is very 
convenient for doing work of this character. It 



CALCULATION OF STOCK; GENERAL FORCINGS. lOI 

may be formed by bending a U out of flat stock, 
bent edgewise, and welding on a handle. 

Three-throw Crank. — Fig. 136 shows what is 
known as a "three-throw" crank. The forging for 




Fig. 136. 

this is first made as shown by the solid lines in Fig. 
137. The forging is drilled and sawed in the 






11 




Fig. 137. 

machine-shop to the dotted lines, and pins rough 
turned, being left as large as possible. The forging 
is returned to the forge-shop, heated, and bent into 
the shape of the finished crank. It is then sent 
to the machine-shop and finished to size. Four- 
throw cranks are also made in this manner. 

The slots are sometimes cut out in the forge-shop 
with a hot chisel, but, particularly on small work, 
it is generally more economical to have them sawed 
out in the machine-shop. This is especially so of 
multiple-throw cranks, which must be twisted. 



I02 FORGE-PRACTICE. 

Knuckles. — There is a large variety of forgings 
which can be classed under one head — such forg- 
ings as the forked end of a marine connecting-rod, 
the knuckle-joints sometimes used in valve-rods, 
and others of this character, such as illustrated in 
Figs. 139, 140, 141, E. 




Fig. 138. 



Cr^ 



X 



Fig. 139. 




Fig. 141. 



Connecting-rod End. — Fig. 138 shows the shaped 
end often used on the crank end of connecting- 
rods. The method of forming this is the same as 
the first step in forging the other pieces above men- 
tioned. 

The stock used for making this should be as wide 



CALCULATION OF STOCK; GENERAL FORCINGS. 



103 



J^ 






as B and somewhat more than twice as thick as A 
The first step is to make two 
fuller cuts as shown at A, Fig. 

142, using a top and bottom 
fuller and working in both 
sides at the same time. When 
working in both sides of a bar 
this way, it should be turned 
frequently, bringing first one 
side, then the other, upper- 
most. In this way the cuts 
will be worked to the same 
depth on both sides, while if 
the work is held in one posi- 
tion, one cut will generally be 
deeper than the other. After 
the cuts are made, the left- 
hand end of the bar is drawn 
out to the proper size and the 
right-hand end punched and split like B. Some- 
times when the length D, Fig. 138, is compara- 
tively short and the stock wide, instead of being 
punched and split, the end of the bar is cut out, as 
shown at C, Fig. 142, with a right angle or curved 
cutter. 

The split ends are spread out into the position 
shown at D, and drawn down to size over the cor- 
ner of the anvil, in the manner illustrated in Fig: 

143. These ends are then bent back into the 
proper position for the finished forging. • Gener- 
ally when the ends are worked out and bent back 
in this manner, a bump is left like that indicated 




Fig. 142. 



I04 



FORGE-PRACTICE. 



by the arrow-point at E, Fig. 142. This should 
be trimmed off along the dotted line. 

Knuckle. — The knuckle, Fig. 139, is started in 
exactly the same way, but after being forged out 




Fig. 143. Fig. 144. 

straight, as above, the tips of these ends are bent 
down, forming a U-shaped loop of approximately 
the shape of the finished knuckle. A bar of iron 
of the same dimension at the inside of the finished 
knuckle is then inserted between the sides of the 
loop and the sides closed down fiat over it, Fig. 
144. 

Forked-end Connecting-rod. — Fig. 140 is made in 
the same manner. The shaft 5 should be drawn 
down into shape and rounded 
up before the other end is 
split. After the split ends 
have been bent back 
straight, the shoulder A 
should be finished up vnth 
a fuller in the manner shown 
in Fig. 145. The rounded 
ends B~B should be formed before the piece is bent 




Fig. 145. 



CALCULATION OF STOCK; GENERAL FORCINGS. IO5 

into shape. The final bending can be done over a 
cast-iron block of the right shape and size if the 
forging is a large one and several of the same kind 
are wanted. 

Hook with Forked End.- — Fig. 141, E is a forging 
which also comes in this general class. This is 
made from |" square stock. The end of the bar is 
first drawn down to ^/J' round. This round end is 
put through the hole of a heading-tool, and the 
square part is split with a hot chisel, the cut wid- 
ened out, and the sides hammered out straight on 
the tool. The different steps are shown in Fig. 
141. 

Wrench, Open-end. — Open-end wrenches of the 
general class shown in Fig. 146 may be made in 




Fig. 146. 

several different ways. It would be possible to 
miake this by the same general method followed 
for making the forked end of the connecting-rod 
described above. Ordinary size wrenches are more 
easily made in the way illustrated in Fig. 147. 

A piece of stock is used, wide enough and thick 
enough to form the head of the wrench. This is 
worked in on both sides with a fuller and the head 
rounded up as shown. A hole is then punched 
through the head and the piece cut out to form 
the opening, as shown by the dotted lines at B. 

This wrench could also be made by bending up 



io6 



FORGE-PRACTICE. 



a U from the proper size flat stock and welding 
on a handle. 




Fig. 147. 

The solid-forged wrench is the more satisfactory. 
Socket-wrench. — The socket- wrench, shown in 
Fig. 148, may be made in several ways. About 

the easiest, on "hurry- 
up" work, is the method 
shown in Fig. 149. Here 
a stub is shaped up the 
sam^e size and shape as 
the finished hole is to be. A ring is bent up of thin 
flat iron and this ring welded around the stub. 



(S 




Fig. 148. 




Fig. 149. 



The width of the ring should of course be equal to 
the length of the hole plus the lap of the weld. 

When finishing the socket, a nut or bolt-head 
the size the wrench is intended to fit should be 



CALCULATION OF STOCK; GENERAL FORCINGS. IO7 





Fig. 150. 



placed in the hole and the socket finished over 
this between swages. 

A better way of making wrenches of this sort is 
to make a forging having 
the same dimensions as 
the finished wrench, but 
with the socket end 
forged solid. The socket 
end should then be 
drilled to a depth slightly 
greater than the socket is 
wanted. The diameter of 
the drill should be, as 
shown in Fig. 150, equal to the shortest diameter of 
the hole. 

After drilling, the socket end is heated red-hot 
and a punch of the same shape as the intended hole 
driven into it. The end of the punch should be 
square, with the corners sharp. As the punch is 
driven in, the corners will shave off some of the 
metal around the hole and force it to the bottom 
of the hole, thus making it necessary to have the 
drilled hole slightly deeper than the socket hole is 
intended to finish. 

While punching, the wrench may be held in a 
heading tool, or if the wrench be double-ended, in a 
pair of special tongs, as shown in Fig. 150. 

Split Work. — There is a great variety of thin 
forgings, formed by splitting a bar and bending 
the split parts into shape. For convenience, these 
can be called split forgings. 

Fig. 151 is a fair sample of this kind of work. 



io8 



FORGE-PRACTICE. 



This piece could be made by taking two flat strips 
and welding them across each other, but, particu- 




FiG. 151. 



Fig. 152. 



larly if the work is very thin, this is rather a diffi- 
cult weld to make. 

An easier way is to take a flat piece of stock of 
the proper thickness and cut it with a hot chisel, 
as shown by the solid lines in Fig. 152. The four 
ends formed by the splits are then bent at right 
angles to each other as shown by the dotted lines, 
and hammered out pointed as required. 

If mxachine steel stock is used, it is not generally 
necessary to take any particular precautions when 




l^IG. 153. 



splitting the bar, but if the material used is wrought 
iron, it is necessary to punch a small hole through 



CALCULATION OF STOCK; GENERAL FORCINGS. 



log 



the bar where the end of the cut comes, to prevent 
the spht from extending back too far. 

Fig. 153 shows several examples of this kind of 
work. The illustrations show in each case the 
finished piece, and also the method of cutting the 
bar. The shaded portions of the bar are cut away 
completely. 

Expanded or Weldless Eye. — Another forging of 
the same nature is the expanded eye in Fig. 154. 





Fig. 154. 



Fig. 155. 



To make this, a fiat bar is forged rounding on the 
end, punched and split as shown. The split is 
widened out by driving a punch, or other tapering 
tool into it, and the forging finished by working 
over the horn of the anvil, as shown in Fig. 155. 

If the dimensions of the eye are to be very accu- 
rate, it will be necessary to make a calculation for 
the length of the cut. This can be done as follows : 
Suppose the forging, for the sake of convenience in 
calculating, to be made up of a ring 3" inside diame- 
ter and sides V wide, placed on the end of a bar 
ly wide. The first thing is to determine the area 
of this ring. To do this find the area of the out- 



no FORG:= -PRACTICE. 

side circle and subtract from it the area of the 

inside circle. (Areas may be found in table, page 
243-) 

Area of outside circle =12.57 sq. in. 

" " inside " = 7 .07 " " 

" " ring = 5.50 



U (( 



The stock, being i^" wide, has an area of i^ 
sq. in. for every inch in length, and it will take 3!" 
of this stock to form the ring, as we must take an 
amount of stock having the same area as the ring. 
This will be practically 3^^/,^'. 

The stock should be punched and split, as shown 
in Fig. 154. It will be noticed that the punch- 
holes are f" from the end, while the stock is to be 
drawn to y^ The extra amount is given to allow 
for the hammering necessary to form the eye. 

Weldless Rings. — Weldless rings can be made in 
the above way by splitting a piece of flat stock and 
expanding it into a ring, or they can be made as 
follows: The necessary volume of stock is first 
forged into a round fiat disc and a hole is punched 
through the center. The hole should be large 
enough to admit the end of the horn of the anvil. 
The forging is then placed on the horn and worked 
to the desired size in the manner indicated in 
Fig. 155. Fig. 156 shows the different steps in 
the process — the disc, the punched disc, and the 
finished ring. 

Rings of this sort are made very rapidly under 
the steam-hammer by a slight modification of this 



CALCULATION OF STOCK; GENERAL FORCINGS. 



method. The discs are shaped and punched and 
then forged to size over a "mandril." A U- 





FlG. 156. 



Fig. 157. 



shaped rest is placed on the anvil of the steam- 
hammer, the mandril is slipped through the hole 
in the disc and placed on the rest, as shown in 
Fig. 157. The blows come directly down upon 
the top side of the ring, it being turned between 
each two blows. The ring of course rests only upon 
the mandril. As the hole increases in size, larger 
and larger mandrils are used, keeping the mandril 
as nearly as possible the same size as the hole. 

Forging a Hub, or Boss. — Fig. 158 is an example 
of a shape very often met with in machine forging: 
a lever, or some flat bar or shank, with a "boss" 





Fig. 158. 



Fig. 159. 



formed on one end. This may be made in two 
ways — either by doubHng over the end of the bar, 
as shown in Fig. 159, and making a fagot-weld of 
sufficient thickness to form the boss, or by taking a 
bar large enough to form the boss and drawing 
down the shank. The second method will be 



112 



rORGE-PRACTICE. 



described, as no particular directions are necessary 
for the weld, and after welding up the end, the 
boss is rounded up in the same way in either case. 
The stock should be large enough to form the boss 
without any upsetting. 

A bar of stock is taken, for the forging shown 
above, 2" wide and 2" thick. The first step is to 
make a cut about 2" from the end, with a fuller, 
like A, Fig. 160. 




Fig. 160. 



The stock, to the right of the cut, is then flat- 
tened down and drawn out to size, as shown at B. 
In drawing out the stock, certain precautions must 
be taken or a " cold-shut ' ' will be formed close to 
the boss. If the metal is allowed to flatten down 
into shape like Fig. C, the corner at X will over- 
lap, and work into the metal, making a crack in 
the work which will look like Fig. E. This 



CALCULATION OF STOCK; GENERAL FORCINGS. II3 

is quite a common fault, and whenever a crack 
appears in a forging close to a shoulder, it is gener- 
ally caused by something of this sort — that is, by 
some corner or part of the metal lapping over and 
cutting into the forging. When one of these cracks 
appears, the only way to remedy the evil is to cut 
it out as shown by the dotted lines in E. For this 
purpose a hot-chisel is sometimes used, with a 
blade formed like a gouge. 

Fig. D shows the proper way to draw out the 
stock; the corner in question should be forged 
away from the boss in such a manner as to grad- 
ually widen the cut. The bar should now be 
rounded up by placing the work over the corner of 
the anvil, as shown in Fig. i6i. First forge off the 




Fig. 161. 

corners and then round up the boss in this way. 
To finish around the corner formed between the 
boss and the flat shank, a set-hammer should be 
used. Sometimes the shank is bent away from 
the boss to give room to work, and a set-hammer, 
or sv/age, used for rounding the boss as shown. 



114 



FORGE-PRACTlCE. 



After the boss is finished, the shank is straightened. 
The boss should be smoothed up with a swage. 

Ladle Shank. — The ladle shank, shown in Fig. 
162, may be made in several ways. It is possible 

to make it solid without 
any welds, or the handle 
may be welded on a fiat 
bar and the bar bent into 
a ring and welded, or the 
ring and handle may be 
forged in one piece and 
the ring closed together by welding. The last- 
mentioned method is as follows : The stock should 
be about i" square. It is necessary to make a 




Fig. 162. 




Fig. 163. 

rough calculation of the amount of this size stock 
required to form the ring of the shank. If the rin^ 



CALCULATION OF STOCK; GENERAL FORCINGS. Ilj 

were made of |"Xi" stock, about 23J" would be 
required; now as i"Xi'' stock is the same width 
and about two and one-half times as thick as 
fXi" stock, every inch of the i"Xi" will make 
about 2\" of |"Xi", consequently about g^" of 
the 1" square will be required to form the ring. 

A fuller cut is made around the bar, as shown 
at A, Fig. 163. This should be made about 9V' 
from the end of the bar. The left-hand end of the 
bar is drawn down to \" in diameter to form the 
handle. If the work is being done under a steam 
or power hammer, enough stock may be drawn 
out to form the entire handle, but if working on 
the anvil, it will probably be more satisfactory to 
draw out only enough stock to make a ' ' stub "4" or 
5" long. To this stub may be welded a round bar 
to form the handle. 

After drawing out the handle, the gY' square 
end of the stock is split, as shown by the dotted 
lines at B. These split ends 
are spread apart, as shown 
at C, forged into shape, and 
bent back to the position 
shown by the dotted lines. 

The ring is completed by ^^^- ^^4- 

cutting the ends to the proper length, scarfing, 
bending into shape, and welding, as indicated in 
Fig. 164. 

If for any reason it is necessary to make a forg- 
ing of this kind without a weld in the ring, it may 
be done by the method shown in Fig. 165. The 
split in this case should not extend to the end of the 




ii6 



rORGE-Jr'RACTICE. 



bar. About f " or |" of stock should be left uncut 
at the end. This split is widened out and the 



J 




Fig. 165. 

sides drawn down and shaped into a ring as desired. 
Starting-lever, — The lever shown in Fig. 166 is a 




Fig. 166 

shape sometimes used for levers used to turn the 

fly-wheels of engines or other heavy wheels by 

gripping the rim. 

The method used in making the lever is shown 

in Fig. 167. The end is first drawn down round 

and the handle formed. 
The other end is then 
split, forged down to 
size, and bent at right 
angles to the handle. 
After trimming to the 
proper length, the flat 
ends are bent into shape. 
^'''- '^7- If this shaped end is 

very heavy, it may be necessary to forge it in the 




CALCULATION OF STOCK; GENERAL FORCINGS. II7 



shape of a solid block, as shown in Fig. i68, and 
then either work in the depression 
shown by the dotted lines, with a 
fuller and set-hammers, or the dotted 
line may be cut out with a hot-chisel. 

Moulder's Trowel. — The moulder's trowel shown 
in Fig. 169 gives an example of the method used in 



Fig. 168. 




Fig. 169. 

making forgings of a large class, forgings having a 
wide thin face with a stem, comparatively small, 
forged at one end. 

The stock to be used for the trowel shown should 
be about |"Xi". This is thick enough to allow 
for the formation of the ridge at R. 







Fig. 170. 

Fig. 170 shows the general method employed. 
The forging is started by making nicks like A, with 
the top and bottom fuller. One end is drawn down 
to form the tang for the handle. This should not 



H8 FORGE-PRACTICE. 

be forged down pointed, as required when com- 
pleted, but the entire length of handle should be 
forged square and about the size the largest part is 
required to finish to. The handle is then bent up 
at right angles, as at B, and the corner forged 
square in the same manner that the corner of a 
bracket is shaped up sharp and square on the out- 
side. 

After this corner is formed, the blade is drawn 
down to size on the face of the anvil. 

When flattening out the blade, in order to leave 
the ridge shown at R, Fig. 169, the work should 
be held as shown at C, Fig. 170. Here the handle 
is held pointing down and against the side of the 
anvil. By striking directly down on the work, and 
covering the part directly over the edge of the anvil 
with the blows, all of the metal on the anvil will be 
flattened down, leaving the metal not resting on 
the anvil unworked. By swinging the piece around 
into a reverse position the other edge of the blade 
may be thinned down. If care be taken to hold 
the trowel in the proper position while thinning 
out the blade, a small triangular-shaped piece next 
the handle will be left thicker than the rest of the 
blade. This raised part will form the ridge shown 
at R, Fig. 169. 

The same result may be obtained by placing the 
trowel, other side up, on the face of the anvil and 
using a set-hammer, or flatter, to thin out the blade. 

Welded Brace. — Fig. 171 shows a form of brace, 
or bracket, sometimes used for holding swinging 
signs and for various other purposes. 



CALCULATlOlSr Of STOCK; GENERAL FORCINGS. 



119 



The bracket in this case is made of round stock; 
but the same method may be followed in making 
one o.'^ fiat or square material. 




FiG. 171. 

The stock is first scarfed on one end and this end 
doubled over, forming a loop, as shown in Fig. 172. 




Fig. 172. 

The loop is welded and then split, the ends straight- 
ened out and flattened into the desired shape as 
illustrated. 




Fig. 173. 

Welded Fork. — The welded fork, shown in Fig. 
173, is made in the same way as the brace de- 
scribed above. 



CHAPTER VII. 



STEAM-HAMMER WORK. 



General Description of Steam-hammer. — The gen- 
eral shape of small and medium steam-hammers 

is shown in Fig. 174. 
This type is known as 
a single - frame ham- 
mer. 

The size of a steam- 
hammer is determined 
by the weight of its 
falling parts ; thus the 
term a 400-lb. ham- 
mer would mean that 
the total weight of 
the ram, hammer-die, 
and piston-rod was 400 
lbs. 

Steam-hammers are 
made in this general 
style from 200 lbs. up. 

The anvil is entire- 
ly separate from the 
frame of the hammer, 
and each rests on a 
separate foundation. 




STEAM-HAMMER WORK. 121 

The foundation for the frame generally takes the 
shape of two blocks of timber or masonry capped 
with timber — one in front and one behind the anvil 
block. The anvil foundation is placed between 
the two blocks of the frame foundation, and is 
larger and heavier. 

The object of separating the anvil and frame is to 
allow the anvil to give under a heavy blow with- 
out disturbing the frame or its foundation. 

Hammer-dies. — The dies most commonly used on 
steam-hammers have flat faces ; the upper or ham- 
mer die being the same width, but sometimes 
shorter in length than the lower or anvil die. 

Tool-steel makes the best dies, but chilled iron 
is also used to a very large extent. Sometimes, 
for forming work, even gray iron castings are used. 
Flat dies made of tool-steel are sometimes used 
without hardening. Dies made this way, when 
worn, may be faced off and used again without 
the bother of annealing and rehardening. 

For special work the dies are made in various 
shapes, the faces being more or less in the shape of 
the work to be formed. When the die-faces are 
shaped to the exact form of the finished piece, the 
work is known as drop-forging. 

Tongs for Steam-hammer "Work. — The tongs used 
for holding work under the steam-hammer should 
be very carefully fitted and the jaws so shaped 
that they hold the stock on all sides. Ordinary 
flat- jawed tongs should not be used, as the work 
is liable to be jarred or slip out sideways. 

Fig. 175 shows the jaws of a pair of tongs fitted 



FORGE-PRACTICE. 




Fig. 175. 



to square stock. Tongs for other shaped stock 

should have the jaws 
formed in a correspond- 
ing way; that is, the in- 
side of the jaws, viewed 
from the end, should have 

the same shape as the cross-section of the stock they 

are intended to hold, and should grip the stock 

firmly on at least three sides. 

Flat- jawed tongs can be easily shaped as above 

in the manner shown in Fig. 176. The tongs are 




Fig. 176. 

heated and held as shown, by placing one jaw, 
inside up, on a swage. The jaw is grooved or 
bent by driving down a top-fuller on it. After 
shaping the other jaw in the same way, the final 
fitting is done by inserting a short piece of stock of 
the proper size in the jaw^s and closing them down 
tightly over this by hammering. 

When fitting tongs to round stock, the finishing 



STEAM-HAMMER WORK. 



123 



may be done between swages, the stock being kept 
between the jaws while working them into shape. 

Tongs for heavy work should have the jaws 
shaped as shown in Fig. 177. When in use, tongs 
of this kind are held by 
slipping a link over the 
handles to force them to- 
gether. On very large sizes, 
this link is driven on with a 
sledge. 

To turn the work easily, 
the link is sometimes made in the shape shown in 
Fig. 178, with a handle projecting from each end. 




Fig. 



177. 



( ) 



Fig. 178. 

Hammer-chisels. — The hot-chisel used for cutting 
work under the hammer is shaped, ordinarily, like 
Fig. 179. This is sometimes made of solid tool- 




FlG. 179. 



Fig. 180. 



steel, and sometimes the blade is made of tool-steel 
and has a wrought-iron handle welded on. Fig. 
180 shows the method of welding on the wrought- 
iron handle. 



124 



FORGE-PRACTICE. 



The handle of the chisel, close up to the blade, is 
hammered out comparatively thin. This is to 
allow the blade to spring slightly without snapping 
off the handle. The hammer will always knock 
the blade into a certain position, and as the chisel 
is not always held in exactly the right way, this 
thin part of the handle permits a little ' ' give ' ' 
without doing any harm. 

The force of the blow is so great when cutting, 
that the edge of the chisel must be left rather 
blunt. The edge should be square across, and not 
rounding. The proper shape is shown at A, Fig. 




Fig. i8i. 



i8i. Sometimes for special work the edge may 
be slightly beveled, as at B or C, but should never 
be shaped like D. 

Sometimes a bar is cut or nicked with a cold- 
chisel under the hammer. 
The chisel used is shaped 
hke Fig. 182, being very 
flat and stumpy to resist the 
crushing effect of heavy blows. The three faces 
of the chisel are of almost equal width. 

Cutting Hot Stock. — Hot cutting is done under the 




Fig. 182. 



STEAM-HAMMER WORK. 



125 



steam-hammer in much the same way as done on 
the anviL 

If the chisel be held perfectly upright, as shown 
at A, Fig. 183, the cut end of the bar will be left 



Fig. 183. 

bulging out in the middle. When the end is wanted 
square the cut should be started with the chisel 
upright, but once started, the chisel should be very 
slightly tipped, as shown at B. When cutting 
work this way the cut should be made about half 
way through from all sides. When cutting off 
large pieces of square stock the chisel should be 
driven nearly through the bar, leaving only a thin 
strip of metal, |^" or Y' thick, joining the twc 
pieces, A, Fig. 184. The bar is then turned over 



Fig. 184. 

on the anvil and a thin bar of steel laid directly on 
top of this thin strip, as shown at B, Fig. 184. 
One hard blow of the hammer sends the thin bar 
of steel between the two pieces and completely 
cuts out the thin connecting strip of metal. This 




126 FORGE-PRACTICE. 

leaves the ends of both pieces smooth, while if the 

chisel is used for cutting 

on both sides, the end of 

one piece will be smooth 

_ and the other will have a 

nn left on it. 

For cutting up into corners on the ends of slots 

bent cutters are sometimes used; such a cutter is 

shown in Fig. 185. These cutters are also made 

curved, and special shapes made for special work. 

General Notes on Steam-hammer. — When working 
under the hammer, great care should always be 
taken to be sure that everything is in the proper 
position before striking a blow. The work must 
rest fiat and solid on the anvil, and the part to be 
worked should be held as nearly as possible below 
the center of the hammer-die ; if the work be done 
under one edge or corner of the hammer-die, the 
result is a "foul" blow, which has a tendency to 
tip the ram and strain the frame. 

When tools are used, they should always be held 
in such a way that the part of the tool touching 
the work is directly below the point of the tool on 
which the hammer will strike. Thus, supposing a 
piece were being cut off under the hammer, the 
chisel should be held exactly upright, and directly 
under the center of the hammer, as shown at A, 
Fig. 186. In this way a fair cut is made. If the 
chisel were not held upright, but slantingly, as 
shown at B, the result of the blow would be as 
shown by the dotted lines, the chisel would be 
turned over and knocked flat, and, in some cases, 



STEAM-HAMMER WORK. I 27 

might be even thrown very forcibly from under 
the hammer. 

When a piece is to be worked out to any great 
extent, the blows should be heavy, and the end of 



/ 



J 



Fig. 1S6. 



the stock being hammered should bulge out slightly, 
like A, Fig. 187, showing that the metal is being 



Fig. 1S7. 

worked clear through. If light blows are used the 
end of the piece will forge out convex, like B, show- 
ing that the metal on the outside of the bar has 
been worked more than that on the inside. If this 
sort of work is continued, the bar will split and 
work hollow in the center, like C. 

Rotind shafts formed between flat dies are very 
liable to be split in this way when not carefully 
handled. 

The faces of the hammer- and anvil-dies are gen- 
erally of the same width, but not always the same 



128 FORGE-PRACTICE. 

length. Thus, when the hammer is resting on the 
anvil, the front and back sides of the two dies are 
in line with each other, while either one or both 
ends of the anvil-die project beyond the ends of 
the hammer-die. 

This is not always the case, however, as in many 
hammers the faces of the two dies are the same 
shape and size. 

Having one die face longer than the other is an 
advantage sometimes when a shoulder is to be 
formed on one side of the "^ork only. 

When a shoulder is to be formed on both sides of 
a piece the work should be placed under the ham- 
mer in such a way that the top die will work in one 
shoulder, while the bottom die is forming the other ; 
in other words, the work should be done from the 
side of the hammer, where the edges of the dies are 
even, as shown in Fig. i88. If the shoulder is re- 
quired on one side only, as in forging tongs, the 




fS 



Fig. 1 88. Fig. 



work should be so placed as to work in the shoulder 
with the top die, while the bottom die keeps the 
under side of the work straight, as in Fig. 189, A. 



STEAM-HAMMER WORK. 



129 



The same object, a shoulder on one side only, 
may be accomplished by using a block, as shown 
at B, Fig. 189. The block may be used as shown, 
or the positions of work and block may be reversed 
and the work laid with flat side on the anvil and 
block placed on top. 

This method of forming shoulders will be taken 
up more in detail in treating individual forgings. 

Tools: Swages. — In general, the tools used in 
steam-hammer work, except in special cases, are 
very simple. 

Swages for finishing work up to about 3" or 4" 
in diameter are commonly made as shown in Fig. 
190. The two parts of the swage are held apart 




Fig. 190. 



by the long spring handle. This spring handle 
may be made as shown at B, by forming it of a sep- 
arate piece of stock and fastening it to the swage, 
by making a thin slot in the side of the block with 
a hot-chisel or punch, forcing the handle into this 
and closing the metal around it with a few light 
blows around the hole with the edge of a fuller. 

Another method of forming the handle (C) is to 
draw out the same piece from which the blocks are 



I30 



rORGE-PRACTICE. 



made, hammering down the center of the stock to 
form the handle, and leaving the ends full size to 
make the swages. 

Swages for large work are made sometimes as 
shown in Fig. 191. The one shown at B is made 




Fig. 191. 

for an anvil-die having a square hole, similar to 
the hardie-hole in an ordinary anvil, near one end. 
The horn on the swage, at x, slips into this hole, 
while the other two projections fit, one on either 
side, over the sides of the anvil. These horns, or 
fingers, prevent the swage from slipping around 
when in use. 




Fig. 192. 

Tapering and Fullering Tool, — As the faces of the 
anvil- and hammer-dies are flat and parallel, it 
is not possible to finish smoothly between the bare 
dies, any work having tapering sides. 



STEAM-HAMMER WORK. 



131 



By using' a tool similar to the one shown in Fig. 
192 tapering work may be smoothly finished. 

Taper Work. — The use of the tool illustrated 
above is shown in Fig. 193. For roughing out 
taper work, the tool is used with the curved side 




ROUGHING 



FINISHING 



Fig. 193. 



down, the straight side being flat with the hammer- 
die. When finishing the taper, the tool is reversed, 
the flat side being held at the desired angle and 
the hammer striking the curved side. This curved 
side enables the tool to do good work through 
quite a wide range of angles. If too great an angle 
is attempted, the tool will be forced from under 
the hammer by the wedging action. 

Fullers. — Fullers such as used for ordinary hand 
forgings are very seldom employed in steam-ham- 
mer work. To take their 
place simple round bars 
are used. When much 
used, the bars should be 
of tool-steel. 

One use of round bars, 
as mentioned above, is il- 
lustrated in Fig. 194, .Here the work, as shown, 




Fig. 



194. 



132 FORGE-PRACTICE. 

has a semicircular groove extending around it, 
forming a "neck." The groove is formed by plac- 
ing a short piece of round steel of the proper size 
on the anvil-die; on this is placed the work, with 
the spot where the neck is to be formed directly 
on top of the bar. Exactly above the bar, and 
parallel to it on top of the work, is held another bar 
of the same diameter. By striking with the hammer, 
the bars are driven into the work, forming the 
groove. The work should be turned frequently 
to insure a uniform depth of groove on all sides; 
for, if held in one position, one bar will work in 
deeper than the other. 

Adjusting Work Under the Hammer. — When work 
is first laid on the anvil the hammer should 
always be lowered lightly down on it in order to 
properly "locate" it. This brings the work flat 
and true with the die-faces; and if held in this 
position (and care should be taken to see that it is) , 
there will be little chance of the jumping, jarring, 
and slipping, caused by holding the forging in the 
wrong position. This is particularly true when 
using tools, as great care must be taken to see that 
the hammer strikes them fairly. If the first blow 
is a heavy one, and the work is not placed exactly 
right, there is danger of the piece flying from under 
the hammer and causing a serious accident. 

As an illustration of the above, suppose that a 
piece be carelessly placed on the anvil, as shown iri 
Fig. 195, the piece resting on the edge of the anvil 
only, not flat on the face, as it should. 

When the hammer strikes quickly and hard two 



STEAM-HAMMER WORK. I33 

things may happen : either the bar will be bent (as 
it will if very hot and soft) or \ / 

it will be knocked into the posi- \ ' 

tion shown by the dotted lines. 
If the hammer be lowered lightly 
at first, the bar will be pushed 
down flat, and assumes the dotted 
position easily, where it may be 
held for the heavy blows. 

Squaring Up Work. — It frequently happens in 
hammer work, as well as in hand forging, that a 
piece which should be square in section becomes 
lopsided and diamond-shaped. 

To correct this fault the forging should be held 
as shown in Fig. 196, with the long diagonal of 




A B C D 



V <C>t)Oa 

Fig. 196. 

the diamond shape perpendicular to the face of the 
anvil. 

A few blows will flatten the work into the shape 
shown at B ; the work should then be rolled slightly 
in the direction of the arrow and the hammering 
continued, the forging taking the shape of C, and, 
as the rolling and hammering are continued, finally, 
the square section D. 

Making Small Tongs. — As an example of manipu- 



134 



FORGE-PRACTICE. 



lation under the hammer, the making of a pair of 
ordinary fiat-jawed tongs is a good illustration. 

Fig, 197 shows the different steps from the straight 
stock to the finished piece. 




Fig. 197. 

The stock is heated to a high heat and bent as 
shown in Figs. 198 and 199. A and B (Fig. 198) 




V_\^L_ 



I^IG. 198. 



Fig. 199. 



are two pieces of fiat iron of the same thickness. 
The stock is placed like Fig. 198, the hammer 
brought down lightly, to make sure that every- 
thing is in the proper position, and then one hard 
blow- bends the stock into shape (Fig. 199). 

Fig. 200 shows the method of starting the eye 



STEAM-HAMMER WORK. I 35 

and working in the shoulder. The bent piece is 
laid flat on the anvil and a piece of flat steel laid on 
top, in such a position that one side of the steel 
will cut into the work and form the shoulder for 





Fig. 200. Fig. 201. 

the jaw of the tongs. The steel is pounded into 
the work until the metal is forged thin enough to 
form the eye. This leaves the work in the shape 
shown in Fig. 201. The part A, Fig. 201, is after- 
ward drawn out to form the handle, the jaw and 
eye are formed up, and, lastly, the eye is punched. 
The forming of the jaw and the punching of the 
rivet-hole should be done with "the hand-hammer, 
and not under the steam-hammer. 

The handle is, of course, drawn out under the 
steam-hammer, but needs no particular descrip- 
tion. For careful finishing, the taper tool illus- 
trated in Fig. 192, may be used, or a sledge and 
swages. 

As a general thing, steam-hammer work does not 
difl^er very much from forging done on the anvil. 
The method of operation, in either case, is almost 
the same; but, when working under the hammer, 
the work is more quickly done and should be han- 
dled more rapidly. 

Crank-shafts. — The crank-shaft, shown in Figs. 



136 



FORGE-PRACTICE. 



128 and 129, is a quite common example of steam- 
hammer work. 

The different operations are about the same as 
described for making it on the anvil. 

A specially shaped tool is used to make the cuts 
each side of the crank cheek. This tool and its 
use are shown in Fig. 202. When the cuts are 




Fig. 202. 



Fig. 203. 



very deep, they should first be made with a hot- 
chisel and then spread with the spreading tool. 
If the shoulder is not very high, both operations, 
of cutting and spreading, may be done at once with 
the spreading tool. 

After marking and opening out the cuts, the 
same precautions, to avoid cold-shuts, must be 
taken as are used when doing the same sort of 
work on the anvil. The work should be held and 
handled much the same as illustrated in Fig. 131, 



STEAM-HAMMER WORK. 



137 



only in this case the sledge and anvil are replaced 
by the top and bottom dies of the steam-hammer. 

A block of steel may be used for squaring up into 
the shoulder, as shown in Fig. 203. If a shoulder 
is to be formed on both sides, one block may be 
placed below and another above the work, some- 
what as shown before in Fig. 194; the round bars 
in the illustration being replaced with square ones. 

Knuckles. — A knuckle such as shown in Fig. 
139 would be made by identically the same 
j)rocess as described for making it on the anvil. 
A few suggestions might be made, however. 

After the end of the bar has been split and bent 
apart, ready for shaping, the work should be han- 
dled, under the hammer, as shown in Fig. 204. It 




Fig. 204. 



should first be placed as shown by the solid lines, 
and as the hammering proceeds, should be gradually 
worked over into the position shown by the dotted 
lines. The other side is worked in the same way. 



138 



FORGE-PRACTICE. 



After drawing out and shaping the ends the 
knuckle is finished by bending the ends together 
over a block, in the same way as shown in Fig. 144, 
the work being done under the hammer. 

Connecting-rod. Drawing Out between Shoulders. — 
The forging illustrated in Fig. 126, while hardly 
the exact proportions of common connecting- 
rods, is near enough the proper shape to be a good 
example of that kind of forging. 

The forging, after the proper stock calculation 
has been made, is started by making the cuts near 
the two ends, as shown in Fig. 127. The distance, 
A, must be so calculated, as explained before, that 



^^^ 
"^-^v 



jJ~K7 



"\r 



Fig. 205. 



Fig. 206. 



the stock represented by that dimension, when 
drawn out, will form the shape, 2" in diameter and 
24" long, connecting the two wide ends. 

The cuts are made with the spreading tool used 
in connection with a short block shaped the same 



STEAM-HAMMER WORK. 1 39 

as the tool, or a second tool, the tools being placed 
one above and one below the work, as shown in 
Fig. 205. 

After making the cuts the stock between them is 
drawn down to the proper size and finished. 

It sometimes happens that the distance .4 is so 
short that the cuts are closer together than the 
width of the die-faces, thus making it impossible 
to draw out the work by using the flat dies. This 
difficulty may be overcome by using two narrow 
blocks as shown in Fig. 206. 

Weldless Rings — Special Shapes. — It is often nec- 
essary to make rings and similar shapes without a 
weld. The simple process is illustrated in Figs. 
155-7. Rings may be made in this way under the 
steam-hammer much more rapidly than is possible 
by bending and welding. To illustrate the rapid- 
ity with which weldless rings can be made, the 
author has seen the stock cut from the bar, the 
ring forged and trued up in one heat. The ring in 
question was about 10" outside diameter, the section 
of stock in rim being about 
i" square. The stock used 
was about 3" square, soft steel. 

A forging for a die to be 
made of tool-steel is shown in 
Fig. 207. F^G- 2°7- 

This is made in the same general way as weld- 
less rings. The stock is cut, shaped into a disc, 
punched, and worked over a mandril into the shape 
shown at A, Fig. 208. 

The lug, projecting toward the center from the 




I40 



FORGE-PRACTICE. 



flat edge of the die, is shaped on a special mandril, 
the work being done as shown at B, the thick side 




Fig. 208. 



of the ring being driven into the groove in the man- 
dril and shaped up as shown at C, where the end 
view of the mandril and ring is shown. 

If the flat edge of the die is very long, it may be 
straightened out by using a flat mandril and work- 




FiG. 209. 

ing each side of the projecting lug after the lug has 
been formed. 



STEAM-HAMMER WORK. 141 

The forging leaves the hammer in the shape 
shown in Fig. 209 at A. The finishing of the sharp 
corner is done on the anvil with hand tools, in 
much the same way that any corner is squared up, 
Figs. B and C giving a general idea of working up 
the corner by using a flatter. 

Punches. — The punches used for this kind of 
work, and in fact for all punching under the steam- 
hammer, should be short and thick. 

A punch made as shown in Fig. 210 is very satis- 
factory for general work. This punch is simply 
a short tapering pin with 
a shallow groove formed 
around it about one third 
of the length from the big 

end. A bar of small 

1 • /Q// • 1 F'*^- 210. 

round iron (| is about 

right for small punches) is heated, wrapped around 

the punch in the groove and twisted tight, as shown. 

The punching is done in exactly the same way 
as with hand tools; that is, the punch is driven to 
a depth of about one half or two thirds the thick- 
ness of the piece, with the work lying flat on the 
anvil; the piece is then turned over, the punch 
started with the work still flat on the anvil, and 
the hole completed by placing a disc, or some other 
object with a hole in it, on the anvil; on this the 
work is placed with the hole in the disc directly 
under where the punch will come through. The 
punch is then driven through and the hole completed. 

The end of the punch must not be allowed to 
become red-hot. If the punch is left in contact 




142 FORGE-PRACTICE. 

with the work too long, it will become heated, and, 
after a few blows, the end will spread out in a mush- 
room shape and stick in the hole. 

To prevent the above, the punch should be lifted 
out of the hole and cooled between every few blows. 

Sometimes, when a hole can be accurately lo- 
cated, an arrangement like that shown in Fig. 211 
is used. The punch in this case is only slightly 
longer than the thickness of the piece to be pierced, 
and is used with the big end down as shown. 





Fig. 211. Fig. 212. 

The punch is driven, together with the piece of 
metal which is cut out, through into the hole in the 
die, which is just enough larger to give clearance to 
the punch. 

A convenient arrangement for locating the punch 
centrally with the hole in the die is shown in Fig. 
212. 

The die should be somewhat larger in diameter 
than the work to be punched. The work is first 
placed in the proper position on the die and the 
punch placed on top. The punch is located by 
using a spider-shaped arrangement made from thin 
iron. This spider has' a central ring with a hole in 
the center large enough to slip easily over the 
punch. Radiating from the ring are four arms, 
three of which have their ends bent down to fit 



STEAM-HAMMER WORK. 



43 



around the outside of the die, the fourth being 
longer and used for a handle. The ends of the bent 
arms are so shaped that where they touch the out- 
side of the die the central hole is exactly over the 
hole in the die. 

After locating the punch with the spider, and 
while the spider is still in place, a light blow of the 
hammer starts the punch, after which the spider is 
lifted off and the punch driven through. 

Forming Bosses on Flanges, etc. — A boss, on a 
flange or other flat piece, such as shown in Fig. 213, 
may be very easily formed by using a few simple 





Fig. 213. Fig. 214. 

tools. The special tools are shown in Fig. 214, 
and are : a round cutter used for starting the boss, 
shown at A, which also shows a section of the tool, 
and a flat disc, shown at B, used for flattening 
and finishing the metal around the boss. 

The stock is first forged into shape slightly 
thicker than the boss is to be finished, as it flattens 
down somewhat in the forging. 

The boss is started by making a cut with the 
circular cutter, as shown at A, Fig. 215, where is 
also shown a section of the forging after the cut 
has been mad-e. 



144 



FORGE-PRACTICE. 



The metal outside of the cut is then flattened 
out, as shown by the dotted Hnes. This flattening 





Fig. 215. 

and drawing out may be done easily by using a 
bar of round steel, as shown at C. The bar is 
placed in such a position as to fall just outside of 
the boss. After striking a blow with the hammer, 
the bar is moved farther toward the edge of the 
work and the piece is turned slightly. In this way 
the stock is roughly thinned out, leaving the boss 
standing. To finish the work, the forging is turned 
bottom side up over the disc, with the boss extend- 
ing down into the hole in the disc, as shown at B. 
With a few blows, the disc is forced up around the 
boss and finishes the metal off smoothly. 

The disc need not necessarily be large enough to 
extend to the edge of the work; for if a disc as 
described above is used to finish around the boss, 
the edge of the work may be drawn down :'n the 
usual way under the hammer. 

A disc is not absolutely necessary in any case; 
but the work may be more carefully and quickly 
finished in this way. 



STEAM-HAMMER WORK. 



145 



Round Tapering Work. — A round tapering shape, 
such as shown at .4, Fig. 216, should be first 




Fig. 216. 



roughly forged into shape. It may be started by 
working in the shoulder next the head with round 
bars, in the way illustrated before in Fig. 194. 

The roughing out may be done with square or 
flat pieces, using them in much the same way; or 
one piece only may be used and the work allowed 
to lie flat on the anvil, with the head projecting 
over the edge. 

After roughing out, the work may be finished 
with swages. As ordinarily used, the swages 
would leave the forging straight, with the oppo- 
site sides parallel. To form a taper, a thin strip 
should be held on top of the upper swage close to 
and parallel with one of the edges, as shown at 
B, Fig. 216. The strip causes the swage to tip 
and slant, thus forming the work tapering. 



CHAPTER VIII. 



DUPLICATE WORK. 



When several pieces are to "be made as nearly 
alike as possible, the work is generally more easily 
done by using "dies" or "jigs." 

Generally speaking, "dies" are blocks of metal 
having faces shaped for bending or forming work. 
The term "jig" may be applied to almost any 
contrivance used for helping to bend, shape, or 
form work. As ordinarily used, a jig, generally, 
is simply a combination of some sort of form or 

flat plate and one or more 
clamps and levers for bend- 
ing. 

Dies, or jigs, for simple 
bending may be easily and 
cheaply made of ordinary 
cast iron; and, for most 
purposes, left rough, or un- 
finished. 

Simple Bending. — The 
bend shown in Fig. 217 is 
a fair example of simple 
work. The dies for making 
this bend are two blocks 
of cast iron made as shown, one simply a rect- 

146 




1 B 



Fig. 217. 



DUPLICATE WORK. I47 

angular block the size of the inside of the bend to 
be made, the other a block having on one side a 
groove the same shape as the outside of the piece 
to be bent. The blocks should be slightly wider 
than the stock to be bent. 

The stock is cut to the proper length, heated, 
placed on the hollow block, and the small block 
placed on top, as shown by the dotted lines at B, 
Fig. 217. The bend is made by driving down the 
small block with a blow of the hammer. 

Work of this kind may be easily done under a 
steam-hammer; and the dies described here are 
intended for use in this way, most of them having 
been designed for, and used under, a 200-lb. ham- 
mer. 

Dies of this kind may be fitted to the jaws of an 
ordinary vise, the bending being done by tighten- 
ing up the screw. 

A die such as described above should have a 
little "clearance"; that is, the opening in the hol- 
low die should be slightly larger at the top than at 
the bottom. The small, or top, die should be made 
accordingly, slightly smaller at the bottom. ' 

To make the dies easier to handle, a hole may be 
drilled and tapped in each block and pieces of 
round bars threaded and screwed into the holes to 
form handles. This is more fully described in the 
following example: 

Fig. 218, A, is a hook bent from stock |" X 1" , to 
fit around the flange of an I beam. The hooks 
were about 6" long when finished. To bend these, 
two cast-iron blocks, or dies, were used, shown at 



148 



rORGE-PRACTICE. 



B. The dies were rough castings. Patterns were 
made by laying out the hook on a piece of 2" white 





Fig. 218. 



Fig. 219. 



pine and then sawing to shape with a band-saw. 
The block was "laid off" as shown in Fig. 219, A, 
the sawing being done on the dotted lines. This 
left the blocks of such a shape that the space be- 
tween them, when they were brought together 
with the upper and lower edges parallel, was just 
equal to the thickness of the stock to be bent. 

Patterns of this kind should be given plenty of 
"draft," which may be quickly and easily done by 
planing the sides, after the blocks are sawed out, 
to taper slightly as shown in Fig. 219, B, where the 
dotted lines show the square sides before being 
planed off for draft as indicated by the solid lines. 

When the castings were made, a ^^/a/' hole was 
drilled in the right-hand end of each block and 
tapped with y tap. A piece of y round iron 
about 30" long was threaded with a die for about 
i-^" on each end and bent up to form the handle. 



DUPLICATE WORK. 149 

A. nut was run on each end and the blocks screwed 
on and locked by screwing the nut up against them, 
making the finished dies as shown in Fig. 218. The 
handle formed a spring, holding the dies far enough 
apart to allow the iron to be placed between 
them. 

As mentioned before, dies of this kind can be 
easily made to cover a variety of work, and are 
very inexpensive. The dies in question, for in- 
stance, required about half an hour's pattern work, 
and about as much time more to fit the handles. 
Calculating shop time at 50 cents per hour and 
castings at 5 cents per pound, and allowing for the 
handle, the entire cost of these dies was less than 
$1.25. 

The same handle can be used for any number of 
dies of about the same size, and if any one of these 
dies should break, it can be replaced at a very 
trifling cost. 

Cast-iron dies of this character will bend several 
hundred pieces and show no signs of giving out, 
although they may snap at the first piece if made 
of hard iron. On an important job it is generally 
wise to cast an extra set to have in case the first 
prove defective. 

Almost any simple shape may be bent in this 
way, and the dies may be used on any ordinary 
steam-hammer with flat forging faces ; and not only 
that, but, not having to be fastened down in any 
way, they may be placed under the hammer, or 
removed, without interfering with other work. 

Loop with Bent-in Ends. — For larger work, it is 



ISO 



FORGE-PRACTICE. 



often better to have a die to replace the lower die 
of the hammer, as in the case mentioned below. 

A number of forgings were wanted like A, Fig. 
220. The stock was cut to the proper length and 




Fig. 220. 

the ends bent at right angles. To make all the 
pieces alike, one end of each piece was first bent, 
as shown at 5, in a vise. The other ends of the 
pieces were then all bent the same way, by hooking 
the bent end over a bar cut to the proper length 
and bending down the straight end over the other 
end of the bar, as shown at C. To make the final 
bend, a cast-iron form was used similar to D. This 
casting was about 2^" thick, and the dovetail- 
shaped base fitted the slot in the anvil base of the 
hammer. When the form was used, the anvil-die 
was removed and the form put in its place. 

The strips to be bent were laid on top of this form 
and a heavy piece of flat stock, i"X2", bent into 



DUPLICATE WORK. 



151 



a U shape to fit the outside of the forging, placed 
on top. A Hght blow of the hammer would force 
the U-shaped piece down, bending the stock into 
the proper shape. Fig. 221 shows the operation, 
the dotted lines indicat- 
ing the position of the 
pieces before bringing 
down the hammer. 

The most satisfactory 
results were obtained 
by bringing the ham- 
mer down lightly on 
the work, then, by turn- 
ing on a full head of 
steam, the ram was 
forced down compara- 
tively slowly, bending 
the stock gradually and ' 
easily. This was much 
more satisfactory than a quick, sharp blow. 

It is not necessary to have the U-shaped piece of 
exactly the same shape as the forging. It is sufifi- 
cient if the lower ends of the U are the proper dis- 
tance apart. As the strip is bent over the form, it 
naturally follows the outline; and it is only neces- 
sary to force it against the form at the lower points 
of the sides. 

The last bend might have been made by using a 
second die fastened to the ram of the hammer in 
place of the U-shaped loop. 

Two dies are necessary for much work ; but these 
are more expensive to make. The upper die can 




Fig. 221. 



152 



FORGE-PRACTICE. 



be easily made to fit in the dovetail on the ram and 
be held in place with a key. 

Right-angle Bending. — Very convenient tools for 
bending right angles, in stock V' or less in thick- 
ness, are shown in Fig. 222. The lower one is made 

to fit easily over the anvil 
of the steam-hammer, the 
projecting lips on either 
side preventing the die 
from sliding forward or 
back. The upper one has 
a handle screwed in, as 
described before. Both 
of these bending tools are 
made of cast iron, the 
patterns being simply 
sawed from a 2" plank. 
Cast-iron dies of this 
kind should be made of a tough, gray iron, rather 
than the harder white iron, as they are less liable to 
break if cast from the former. 

• Many of the regular hammer dies, that is, the dies 
with fiat faces for general forging, are made of cast 
iron ; but the iron in this case is of another quality 
— chilled iron — the faces being chilled, or hardened, 
for a depth of an inch or more. 

Circular Bending — Coil Springs. — The dies de- 
scribed before have been for simple bends; the 
blows, or bending force, coming from one direction 
only. In the following example, where a complete 
circle, or more than a circle, is formed, an arrange- 
ment of a different nature is required. 




Fig. 



DUPLICATE WORK. 



153 



The spring shown in Fig. 223 is an example of 
this kind. In this particular case the bending 
was done cold; but for hot bending the operation 
is exactly the same. 





Fig. 223. 



Fig. 224. 



This jig (Fig. 224) w^as built upon a base-plate, A, 
about I" thick, having one end bent down at right 
angles for clamping in an ordinary vise. 

The post E was simply a i" stud screwed into 
the plate. B was a piece of |"Xi" stock about 
2" long, fastened dow^n with two rivets, and serv^ed 
as a stop for clamping the stock against while bend- 
ing. C was a lever made of a piece of fXi" 
stock about 10" long, having one end ground 
rounding as shown. This lever turned on the 
screw F, threaded into the base-plate. D was the 
bending lever, ha^dng a hole punched and forged 
in the end large enough to turn easily on the stud 
E. On the under side of this lever was riveted a 
short piece of iron having one end bent down at 
right angles. This piece was so placed that the 
distance between stud E and the inside face of bent 
end, when the lever was in position for bending, was 



154 rORGE-PRACTlCE. 

about '^f f,y greater than the f^iickness of the stock 
to be bent. 

When in operation, the stuck to be bent was 
placed in the position shown in the sketch, the 
lever C pulled over to lock it in place, and the bend- 
ing lever D dropped over it in the position shown. 
To bend the stock, the lever was pulled around in 
the direction of the arrow and as many turns taken 
as were wanted for the spring, or whatever was 
being bent. By lifting off the bending lever and 
loosening the clamping lever the piece could be 
slipped from the stud. 

With jigs of any kind a suitable stop should 
always be provided to place the end of the stock 
against, in order to insure placing and bending all 
pieces as nearly as possible alike. 

Drop-forgings. — Strictly speaking, drop-forgings 
are forgings made between dies in a drop-press or 
forge. Each die has a cavity in its face, so shaped 
that when the dies are in contact the hole left has 
the form of the desired forging. One of the dies is 
fastened to the bed of the drop-press, directly in 
line with and under the other die, which is keyed 
to the under side of the drop, a heavy weight run- 
ning between upright guides. The forging is done 
by raising the drop and allowing it to fall between 
the guides of its own weight. 

There are generally two or more sets of cavities 
in the die-faces, one set being used for roughing 
out, or "breaking down," the stock roughly to 
shape ; another set for finishing. 

The dies mentioned above would be known as 



DUPLICATE WORK. I 55 

the "breaking-down" and "finishing" dies, re- 
spectively. Sometimes several intermediate dies 
are used. 

In a general way, the term drop-forging may be 
used to describe almost any forging formed be- 
tween shaped dies whether made by a drop-press or 
other means. 

Taking the word in its broadest meaning, the 
example given below might be called a drop-forg- 
ing, the work being done between shaped dies. 

Eye-bolt — Drop-forging. — The example in ques- 
tion is the eye-bolt given in Fig. 225. The differ- 
ent steps in the making, and 
the dies used, are shown in Fig. 
226. 

Round stock is used, and first 
shaped like A, Fig. 226, the 
forming being done in the die 
B. This die, as well as the other 
one, is made in the same way 
as ordinary steam-hammer swages ; that is, simply 
two blocks of tool-steel fastened together with a 
spring handle. The inside faces of the blocks are 
formed to shape the piece as shown. 

The stock is revolved through about 90 degrees 
between each two blows of the steam-hammer, and 
the hammering continued until the die-faces just 
touch. 

For the second step the ball is flattened to about 
the thickness of the finished eye between the bare 
hammer-dies. The hole is then punched, under 
the hammer, with an ordinary punch. 




156 



FORGE-PRACTICE. 



The forging is finished with a few blows in the 
finishing die D, which is shown by a sectional cut 
and plan. This die is so shaped that, when the 
two parts are together, the hole left is exactly the 











' ^_/^^ 


\ 

\ 










^ '"N^ 


/ 
/ 




> 


c 


B 




D 


rt 










r\ 




( o : 








'^^ 


Ly 



SECTION ATX-X 



Fig. 226. 

shape of the finished forging. In the first die, how- 
ever, it should be noticed that the holes do not con- 
form exactly to the desired shape of the forging; 
here the holes, instead of being semicircular, are 
rounded off considerably at the edges. This is 
shown more clearly in Fig. 227, A, where the dotted 
lines show the shape of the forging, the solid lines 
the shape of the die. 

The object of the above is this : If the hole is a 
semicircle in section, the stock, being larger than 
the small parts of the hole, after a blow, is left 



DUPLICATE WORK. 



157 




Fig. 227. 



like B, the metal being forced out between the 

flat faces of the die and 

forming 'fins.' When 

the bar is turned and 

again hit, these fins are 

doubled in and make a 

bad place in the forging. 

When the hole is a 
modified semicircle, as de- 
scribed above, the stock 
will be formed like C, 
and may be turned and 
worked without injury 
or danger of cold-shuts. 

Forming Dies Hot. — Making dies for work of the 
above kind is generally an expensive process, par- 
ticularly if the work be done in the machine-shop. 

Rough dies for this kind of work may be cheaply 
made in the forge-shop by forming them hot. 

The blocks for the dies are forged and prepared, 
and a blank, or 'master,' forging the same shape 
and size as the forgings the dies are expected to 
form is made from tool-steel and hardened. 

The die ■ blanks are then heated, the master 
placed between them, and the dies hammered to- 
gether, the master being turned frequently during 
the hammering. 

This, of course, leaves a cavity the shape of the 
master. 

When two or more sets of dies are necessary 
there, of course, must be separate masters for each 
set of dies. Dies made in this way will have the 



158 FORGE-PRACTICE. 

corners of the cavities rounded off, as the metal is 
naturally pulled away during the forming, leaving 
the corners somewhat relieved. 

Dies such as described above may be used to 
advantage under almost any steam-hammer. 

For spring hammers, helve hammers, and power 
hammers generally the die faces may be formed 
the same as above; but the die-blocks should be 
fastened to the hammer and anvil of the power 
hammer itself, replacing the ordinary dies. 

Cast-iron Dies. — Much drop-forging is done with 
cast iron dies, and for rough work that is not too 
heavy they are very satisfactory, and the first cost 
is very small as compared with the steel dies used 
for the same purpose. 

Drop-forging can be done in this way with the 
steam-hammer, by keying the dies in the dovetails 
made for the top and bottom hammer-dies. 

Welding in particular is done in this way, as the 
metal to be worked is in such a soft condition that 
there is little chance of smashing the die. 



CHAPTER IX. 

TOOL FORGING AND TEMPERING. 

It is assumed that the general method of tem- 
pering as described before is understood, and only 
special directions will be given in particular cases 
in the following pages. 

Forging Heat.- — Any tool-steel forging on which 
there is any great amount of work to be done 
should have the heavy forging and shaping done 
at a yellow heat. At this heat the metal works 
easily and properly, and the heavy pounding re- 
fines the grain and leaves the steel in proper condi- 
tion to receive a cutting edge. When a tool is 
merely to be smoothed off or finished, or forged to 
a very slight extent, the work should be done at a 
much lower heat, just above the hardening tem- 
perature. 

Very little hammering should be done at any 
heat below the hardening temperature. 

Cold-chisels. — The ordinary cold-chisel is so sim- 
ple in shape that no detail directions are necessary 
for forging. The stock should be heated to a yel- 
low heat and forged into shape and finished as 
smooth as possible. If properly forged the end, or 
edge, will bulge out, like Fig. 228. This should be 
nicked across with a sharp hot-chisel (but not cut 

159 



l6o FORGE-PRACTICE. 

off), as shown at C, and broken off after the tool 
^as been hardened. This broken edge will then 




Fig. 228. 

show the grain and indicate whether the steel has 
been hardened at a proper temperature. 

When hardening, the chisel should be heated red- 
hot as far back from the point as the line A, Fig. 
229. Great care must be taken to heat slowly 
( — 1 enough to heat the thicker part of the 
chisel without overheating the point. If 
the point does become too hot, it should 
not be dipped in water to cool off, but 
allowed to cool in the air to below the 
hardening heat and then reheated more 
carefully. 
^ When the chisel has been properly heated 
to the hardening heat, the end should be 
' hardened in cold water back to the line B, 
Fig. 235. As soon as the end is cold the 
chisel should be withdrawn from the 
water and one side of the end polished 

Fig. 229. rr • -i ■ f 1 • 

off With a piece 01 emery or something 
of that nature, as described before. 

The part of the chisel from A to B will be still 
red-hot, and the heat from this part will gradually 



TOOL FORGING AND TEMPERING. ' l6i 

reheat the point of the tool. As the metal is re- 
heated the polished surface will change color, show- 
ing at first yellow, brown, and at last purple. As 
soon as the purple, almost blue color reaches the 
nick at the end, the chisel should again be cooled, 
this time completely. The waste end may now be 
snapped off and the grain examined. To test for 
proper hardness, try the end of the chisel with a 
fine file, which should scratch it slightly. If the 
grain is too coarse, the tool should be rehardened 
at a lower temperature, while if the metal is too 
soft, it should be rehardened at a higher tempera- 
ture. 

Cape-chisel. — The cape-chisel, illustrated in Fig. 
230, is used for cutting grooves and working at the 




bottom of narrow channels. The cutting edge A 
should be wider than any part of the blade back to 
B, which should be somewhat thinner in order that 
the blade may "clear" when working in a slot the 
width of A. 

The chisel is started by thinning down B over 
the horn of the anvil, as shown at A, Fig. 231. The 
finishing is done with a hammer or flatter in the 
manner illustrated at B. The chisel should not 
be worked flat on top of the anvil, as shown at C, 
as this knocks the blade out of shape. 



l62 



FORGE-PRACTICE. 



The cape-chisel is tempered the same as a cold- 
chisel. 




Fig. 231. 



Square- and Round-nose Cape-chisels. — The chisels 
are started in the same way as an ordinary cape- 
chisel, the ends being left somewhat more stubby. 

The end is then finished round or square, as 
shc'vn in Fig. 232, and tempered the same as a 
cold -chisel. 

Round-nose cape-chisels are sometimes used to 
center drills, and are then called "centering" 
chisels. 

Lathe-tools in General. — The same general forms 
of lathe -tools are followed in nearly all shops; but 
in different places the shapes are altered somewhat 
to suit individual tastes. 



TOOL FORGING AND TEMPERING. 



163 



Right- and Left-hand Tools. — Such tools as side 
tools, diamond points, etc., are generally made in 
pairs — that is, right- and left-handed. If a tool is 
made with the cutting edge on the left-hand side 
(as the tool is looked at from the top with the shank 




Fig. 232. 

of the tool nearest the observer), it would be called 
a right-hand tool. That is, a tool which begins its 
cut at the right-hand end of the piece and cuts 
towards the left is known as a right-hand tool; 
one commencing at the left-hand end and cutting 
towards the right would be known as a left-hand 
tool. 

The general shape of right- and left-hand tools 
for the same use is practically the same excepting 
that the cutting edges are on opposite sides. 

Round-nose and Thread Tools, — Round-nose and 
thread tools are practically alike, the difference 
being in the grinding of the end. The thread tool 
is sometimes made a little thinner at the point. 

The round-nose tool, Fig. 233, is so simple in 
shape that no description of the forging is neces- 
sary. Care must be taken to have proper ' ' clear- 
ance." The cutting is all done at or near the 



164 



FORGE-PRACTICE. 



end, and the sides must be so shaped that they 
"clear" the upper edge of the end. In other 
words, the upper edge of the shaped end must be 




Fig. 233. 

wider at every point than the lower edge, as shown 
by the section. 

For hardening, the tool should be heated about 
as far as the line A, Fig. 234, and cooled up to the 




Fig. 



234- 



line B. Temper color of scale should be light yel- 
low. 

Cutting-off Tools. — Cutting-off tools are forged 
with the blade either on one side or in the center of 
the stock. The easier way to make them is to forge 



TOOL FORGING AND TEMPERING. 



165 



the blade with one side flush with the side of the 
tool. A tool forged this way is shown in Fig. 235. 




Fig. 235. 

The cutting edge is the extreme tip of the blade, 
and the cutting is done by forcing the tool straight 
into the work, the edge cutting a narrow groove. 
The only part of the tool which should touch the 
work is the extreme end, or cutting edge; there- 
fore the th'ckest part of the blade must be the cut- 
ting edge, the sides gradually tapering back in all 
directions and becoming thinner, as shown in the 
drawing, A being wider than B. 

The cutting edge should be slightly above the 
level of the top of the tool, or, in other words, the 
blade should slant slightly upwards. 

The clearance angle at the end of the tool is 
about right for lathe-tools ; but for plainer tools the 
end should be made more nearly square, about as 
shown by the line X — X. 

For hardening, the heat should extend to about 
the line C — C, and the end should be cooled to 
about the line D — D. Temper color should be light 
yellow. 

The tool may be forged by starting with a fuller 
cut, as shown at A, Fig. 236. The blade is roughly 



1 66 



FORGE-PRACTICE. 



forged into shape with a sledge, or, on hght stock, 
a hand-hammer, working over the edge of the anvil 
to form the shoulder in the manner shown at B. 
This leaves the end bulged out and in rough shape, 




Fig. 236. 

similar to C. The end should be trimmed off with 
a sharp hot-chisel along the dotted line. 

The finishing may be done over the corner of the 
anvil, using a hand-hammer or flatter, in the same 
way as when starting the tool; or a set-hammer 
may be used, as shown at D. 

Care must be taken to have proper clearance on 
all sides of the blade. It is a good plan to upset 
the end of the blade slightly by striking a few light 
blows the last thing on the end at the cutting 
edge, then ardding a little clearance. 



TOOL FORGING AND TEMPERING. 



167 



When a tool is wanted with the blade forged in 
the center of the shank, the two shoulders are 
formed by using a set-hammer and working at the 
edge of the anvil face, letting the corner of the 
anvil shape one shoulder while the set-hammer is 
forming the other. This process has been de- 
scribed before under the general method of form- 
ing double shoulders. 

Bent Cutting-off Tool. — The bent cutting-off tool, 




Fig. 237. 

Fig. 237, is made and tempered exactly the same 
as the straight tool,, excepting that the blade is 
bent backward toward the shank through an angle 
of about 45 degrees. 




Fig. 238. 

Boring Tool. — The boring tool, illustrated in Fig. 
238, needs no particular description. The length 
of the thin shank depends upon the depth of the 



l68 fORGE-PRACTICE. 

hole the tool is to be used in, but, as a general 
rule, should not be made any longer than necessary. 

This thin shank is started with a fuller cut and 
drawn out in much the same way as the cutting-off 
tool was started. 

The cutting edge is at the end of the small, bent 
nose. The only part of the tool required tempered 
is the bent nose, or end, which should be given the 
same temper color as the other lathe-tools — light 
yellow. 

Internal Thread Tool. — This tool, used for cut- 
ting screw threads on the inside of a hole, is forged 
to the same shape as the boring tool described 
above, the end being afterward ground somewhat 
differently. 

Diamond-points. — These tools are made right and 
left. 



Fig. 239. 

There are several good methods of making these 
tools; but the one given below is about as quick 
and easy as any, and requires the use of no tools 
excepting the hand-hammer and sledge. 

The diamond-point is started as shown at A, Fig. 
240, by holding the stock at an angle of about 45 
degrees over the outside edge of the anvil. It is 
first slightly nicked by being driven down with a 



TOOL FORGING AND TEMPERING. 



169 



sledge against the corner, and the bent end down 
to the dotted position with a few blows, as indi- 
cated by the arrow. 





Fig. 240. 



This end is further bent by holding and striking 
as illustrated at B. The diamond shape is given 
to the end by swinging the tool back and forth and 



170 



FORGE-PRACTICE. 



striking as shown at C, which gives a side and end 
view of tool in position on the anvil. 

The tool is finished by trimming the end with 
a sharp hot-chisel and so bending the end as to 
throw the top of the nose slightly to one side, giv- 
ing the necessary side ' 'rake" as shown in Fig. 239. 

When hardening, the end should be dipped as 
shown at D and the temper drawn to show light- 
yellow scale. 

Tools like the above made of stock as large as 
y X i" may be made using the hand-hammer alone. 




Fig. 241. 

Side Tools. — Side tools, or side-finishing tools, as 
they are also called, are generally made about the 
shape shown in Fig. 241. These tools are made 
right and left and are also made bent. The bent 



TOOL FORGING AND TEMPERING. 



171 



side tools have the ends forged the same; but the 
blade is afterward bent toward the shank, cutting 
edge out, at an angle of about 45 degrees. 

The side tool may be started by making a fuller 
cut as shown at A, Fig. 241, near the end of the 
stock. 

The part of the stock marked x is then drawn 
out by using a fuller turned in the opposite direc- 
tion, working the stock down into the shape shown 
at B. The blade is smoothed up with a set-ham- 
mer and trimmed with a hot-chisel along the dotted 
lines on C. The curved end of the blade is smoothed 
up and finished with a few blows of the hand-ham- 
mer. 

The tool is finished by giving the proper ' ' offset ' ' 
to the top edge of the blade. This is done by plac- 
ing the tool, flat-side down, with the blade ex- 
tending over, and the end of the blade next the 
shank about one-eighth of an inch beyond, the 
outside edge of the anvil. A set-hammer is placed 
on the blade close up to the shoulder and slightly 
tipped, so that the face of the hammer touches the 
thin edge of the blade only, as illustrated at D. 
One or two light blows with the sledge will give 
the necessary offset, and after straightening the 
blade the tool is ready for tempering. 

It is very important on these tools, as well as on 
all others, to have the cutting edge as smooth and 
true as possible; it is, therefore, best, the very last 
thing, to smooth up this part of a tool, using the 
hand- or set-hammer. Above all things, the cut- 
ting edge must not be rounded off, as this necessi- 



172 



FORGE-PRACTICE. 



tates grinding down the edge until the rounded 
part has been completely ground off. 

While the side tool is being heated for temper- 
ing, it should be placed in the fire with the cutting 
edge up. It is more easy to avoid overheating of 
the edge in this way. 

The blade is hardened by dipping in water as 
shown at E, only a small part of back, A, of the 
blade extending above the water and remaining 
red-hot. The tool is taken from the water, quickly 
polished on the flat side, and the temper drawn to 
show a very light yellow. The same color should 
show the entire length of the cutting edge. If the 
color shows darker at one end, it indicates that 
that end of the blade was not cooled enough, and 
the tool should be rehardened, this time tipping 
the tool in such a way as to bring that end of the 
blade which was before too soft deeper in the water. 

Centering Tool. — The centering tool, Fig. 242, 
used for starting holes on face-plate and chuck 

work, is started in 
1(1} y much the same way 




Fig. 242. 



IS the boring tool. 
The end is flattened 
out thin and trimmed 
into shape with a hot- 
chisel. The right- 
hand side of the end should be cut from the top side 
and the left-hand from the other, leaving the end 
the same shape as a flat drill. 

Tempered the same as other lathe-tools. 
Finishing Tool. — This tool. Fig. 243, is started by 



TOOL rORGING AND TEMPERING. 



173 



D;Lnxi 



bending the end of the stock down over the edge of 
the anvil in the same way 
as when starting the diamond- 
point. 

The end is flattened and 
widened by working with a 
hand- or set-hammer, as ^^^- ^43- 

shown at A, Fig. 244. This leaves the end bent 
out too nearly straight; but, after being shaped, it 
is bent into the proper angle, in the manner illus- 





FiG. 244. 

trated at B. The blade will then probably be bent 
somewhat like C, but a few blows with a hammer, at 
the point and in the direction indicated by the 
arrow, will straighten this out, leaving it like D. 
After trimming and smoothing, the tool is ready 



174 FORGE-PRACTICE. 

for tempering. The blade should be tempered to 
just show the very lightest yellow at cutting edge. 

When a tool of this kind is to be used on a planer, 
the front end should make more nearly a right angle 
with the bottom; or, in other words, there should 
be less front ' ' rake" or ' ' clearance." 

Flat Drills. — The flat drill. Fig. 245, needs no 



Fig. 24s. 

description, as the forging and shaping are very 
simple. The end should be trimmed the same as 
the centering tool. The size of the tool is deter- 
mined by the dimension A, this being the same size 
as the hole the drill is intended to make; thus, if 
this dimension were i ", the drill would be known 
as an inch drill. 

The temper is drawn to show a dark-yellow scale. 

Hammers. — As a general rule, when making ham- 
mers of all kinds by hand the eye is made first. A 
bar of steel of the proper size and convenient length 
for handling is used, and the hammer forged on 
the end, as much forging and shaping as possible 
being done before cutting the hammer from the 
bar. 

The hole for the eye is punched in the usual way 
at the proper distance from the end of the bar, 
using a punch having a handle (Fig. 70). 

The nose of the punch is slightly smaller but has 
the same shape as the eye is to finish. Great care 



TOOL FORGING AND TEMPERING. 175 

must be taken to have the hole true and straight. 
It is very difficult and sometimes impossible to 
straighten up a crooked hole. 

After punching the eye, the sides of the stock 
are generally bulged out, and to prevent knock- 
ing the eye out of shape while forging down this 
bulge a drift-pin. Fig. 246, is used. This is made 




SECTION AT 
A-A 



Fig. 246. 



of tool-steel and tapers from near the center to- 
ward each end, one end being somewhat smaller 
than the other. The center of the pin is the same 
shape and size as the eye is to be in the hammer. 

When the bar has been heated the drift-pin is 
driven tightly into the hole and the bulge forged 
down in the same way (B, Fig. 248) as a solid bar 
would be treated. When the drift-pin becomes 
heated it must be driven out and cooled, and under 
no circumstances should the bar be heated with 
the pin in the hole. The pin should always be 
used when there is danger of knocking the eye out 
of shape. 

The steel used for hammers, and ' ' battering 
tools" in general, should be of a lower temper (con- 
tain less carbon) than that used for lathe-tools. 

The eye of a hammer should not be of uniform 
size throughout, but should be larger at the ends 



176 



FORGE-PRACTICE. 



and taper slightly toward the center, as illustrated 
in Fig, 247, which shows a section of a hammer cut 
through the center of the eye. 
When the eye is made in this 
way (slightly contracted at 
the middle), the hammer- 
handle may be driven in 




Fig. 247. 



tightly from one end ; then by driving one or more 
wedges in the end of the handle it is held firmly 
in place and there is no chance for the head to 
work up or down. 

Cross-pene, Blacksmith's or Riveting Hammer.— A 
hammer of this kind is shown at C, Fig. 6. 




Fig, 248. 



The different steps in the process of forging are 
illustrated in Fig. 248. First the eye is punched 
as shown at A. The pene is then drawn out and 



TOOL FORGING AND TEMPERING. 



177 



shaped and a cut started at the point where the 
end of the hammer will come (C), the drift-pin 
being used, as shown at B, while forging the metal 
around the eye. 

The other end of the hammer is then worked up 
into shape, using a set-hammer as indicated at D. 

When the hammer is as nearly finished as may be 
while still on the bar, it is cut off with a hot-chisel, 
leaving the end as nearly square and true as pos- 
sible. 

After squaring up and truing the face the ham- 
mer is tempered. 

For tempering, the whole hammer is heated in a 
slow fire to an even hardening heat; while harden- 
ing, the tongs should grasp the side of the hammer, 
one jaw being inserted in the eye. 

Both ends should be tempered, this oeing done 
by hardening first one end, then the other. 

The small end is hardened first by cooling, as 
shown in Fig. 249. As soon as this end has cooled, 
the position is instantly 
reversed and the large 
end of the hammer dipped 
in the water and hard- 
ened. While the large 
end is cooling, the smaller 
one is polished and the 
temper color watched for. 
When a dark-brown scale 
appears at the end the Fig. 249. 

hammer is again reversed, bringing the large end 
uppennost and the pene in the water. The face 




ly^ FORGE-PRACTICE. 

end is polished and tempered in the same way as 
the small end. If the large end is properly hard- 
ened before the temper color appears on the small 
end, the hammer may be taken completely out of 
the water and the large end also polished, the 
colors being watched for on both ends at once. As 
soon as one end shows the proper color it is promptly 
dipped in water, the other end following as soon as 
the color appears there. 

Under no circumstances should the eye be cooled 
while still red-hot. 

For some special v/ork hammer-faces must be 
very hard; but for ordinary usage the temper as 
given above is very satisfactory. 

Ball Pene-hammer. — The ball pene-hammer. Fig. 
5, is started by punching the eye. 

The hammer is roughed out with two fullers in 
the manner illustrated at A, Fig. 250. 

The size of stock used should be such that it will 
easily round up to form the large end of the hammer. 

After the hammer is roughed out as shown at A, 
the metal around the eye is spread sidewise, using 
two fullers as illustrated at S, a set-hammer being 
used for finishing. This leaves the forging like C. 
The next step is to round and shape the ball, which 
is forged as nearly as possible to the finished shape. 

After doing this a cut is made in the bar where 
the face of the hammer will come, and the large end 
rounded up, leaving the work like D. 

The necked parts of the hammer each side of 
the eye are smoothed and finished with fullers of 
the proper size. Some hammers are made with 



TOOL FORGING AND TEMPERING. 



179 



these necks round in section, but the commoner 
shape is octagonal. 

After smoothing off, the hammer is cut from the 
bar and the face forged true. Both ends are ground 
true and tempered. This hammer should be tem- 




FlG. 250. 



pered in the same way as described above for tem- 
pering the riveting-hammer. 

Ball pene-hammers may be made with the steam- 
hammer in practically the same way as described, 
only substituting round bars of steel for use in 
place of fullers. 

Sledges. — Sledges are made and tempered in the 
same general way as riveting-hammers. Sledges 
may be forged and finished almost entirely under 
the steam-hammer. 



l8o FORGE-PRACTICE. 

Blacksmith's Cold-chisel. — This tool (Fig. 2) is 
forged in practically the same way as the cross-pene 
hammer described before. The end, of course, is 
drawn out longer and thinner, the thin edge com- 
ing parallel with the eye instead of at right angles 
to it. 

The cutting edge only of the chisel is tempered. 
The temper should be drawn to show a bluish 
.scale just tinged with a little purple. Under no 
circumstances should the head of the chisel be 
hardened, as this would cause the end to chip 
when in use and might cause a serious accident. 

The tool shown in Fig. 192 may be used to ad- 
vantage when making hot- or cold- chisels with the 
steam-hammer. By using this tool, as illustrated 
in Fig. 193, the blade of the chisel may be quickly 
drawn out and finished. 

Hot-chisel. — After forming the eye of the hot- 
chisel (Fig. 2), the blade is started by making the 
~-,___^ two fuller cuts, as il- 

"■~~----ZlI]^^^p>\,-___^ lustrated in Fig. 251. 

(^^-^^^TTjf "~ ■--■--. ^ The end is drawn 
— ^""--^^ — ^^--^^-"'^ down as indicated by 

the dotted lines. The 
" ' head is shaped and 

the chisel cut from the bar in the same way that 
the riveting-hammer was treated. 

This chisel should have its cutting edge tem- 
pered the same as that of the cold-chisel. 

Hardies. — Hardies such as shown in Fig. 2 
should be started by drawing out the stem. This 
stem is drawn down to the right size to fit the 



TOOL FORGING AND TEMPERING. l8i 

hardy-hole in the anvil and the piece cut from the 
bar. This is heated, the stem placed in the hole 
in the anvil, and the piece driven down into the 
hole and against the face of the anvil, thus forming 
a good shoulder between the stem and the head of 
the hardy. 

After forming the shoulder, the blade is worked 
out, starting by using two fullers in the same way 
as w^hen starting the hot-chisel blade. 

The cutting edge should be given the same tem- 
per as a cold-chisel. 

Blacksmith's Punches. — Punches shaped similar 
to Fig. 70 are started the same manner as the hot- 
chisel, excepting that 
the fuller cuts are 
made on four sides, as 
shown in Fig. 252. 
The end is then drawn 
out to the shape Fig. 252. 

shown by the dotted 
Knes. 

Temper same as cold-chisel. 

Set-hammers — Flatters. — The set-hammer. Fig. 
15, is so simple that no directions are necessary for 
shaping. The face only should be tempered and 
that should show a dark-brown or purple color. 

Flatters such as shown in Fig. 14 may be made 
by upsetting the end of a small bar, the upset part 
forming the wide face; or a bar large enough to 
form the face may be used and the head, or shank, 
drawn down. 

The eye should be punched after the face has been 




l82 



FORGE -PRACTICE. 




Fig. 



253- 



made. The face should be tempered to about a 

blue. 

When many are to be 
made a swage - block 
similar to Fig. 253 
should be used. Half 
only of the block is 
shown in the figure, the 
other half being cut away 
to show the shape of the 

hole which is the size of the finished flatter. 

When using this block the stock is first cut to 

the proper length, heated, placed in the hole, and 

upset. 

Swages. — Swages may also be made in a block 

similar to the one used for the flatter. The swage 

should be first upset in the block and the crease 

formed the last thing. The crease may be made 

with a fuller or a bar of round stock the proper 

size. 

Fullers. — Fullers are made in the same way as 

swages. 

All of these tools may be upset and forged under 

the steam-hammer, using the die, or swage, blocks 

as described above. The swage-blocks may be 

made of cast iron. 



CHAPTER X. 

MISCELLANEOUS WORK. 



Shrinking. — When iron is heated it expands, and 
upon being cooled it contracts to practically its 
original size. 

This property is utilized in doing what is known 
as ' ' shrinking." 




Fig. 254. 

A common example of this sort of work is illus- 
trated in Fig. 254, showing a collar "shrunk" on a 
shaft. The collar and shaft are made separately. 
The inside diameter of the hole through the collar 
is made slightly less than the outside diameter of 
the shaft. When the collar and shaft are ready 
to go together the collar is heated red-hot. The 
high temperature causes the metal to expand and 
thus increases the diameter of the hole, making 
it larger (if the sizes have been properly propor- 
tioned) than the outside diameter of the shaft. 
The collar is then taken from the fire, brushed 
clean of all ashes and dirt, and slipped on the shaft 

183 



184 FORGE-PRACTICE. 

and into the proper position, where it is cooled as 
quickly as possible. This cooling causes the collar 
to contract and locks it firmly in place. 

If the collar be al'owed to cool slowly it will heat 
the shaft, which will expand and stretch the collar 
somewhat; then, as both cool together and con- 
tract, the collar will be loose on the shaft. 

This is the method used for shrinking tires on 
wheels. The tire is made just large enough to slip 
on the wheel when hot, but not large enough to go 
on cold. It is then heated, put in place, and 
quickly cooled. 

Couplings are frequently shrunk on shafts in this 
way. 

Brazing.-— Brazing, it might be said, is soldering 
with brass. 

Briefly the process is as follows: The surfaces to 
be joined are cleaned thoroughly where they are to 
come in contact with each other. The pieces are 
then fastened together in the proper shape by 
binding with wire, or holding with some sort 
of clamp. The joint is heated, a flux (gener- 
ally borax) being added to prevent oxidation of 
the surfaces, and the "spelter" (prepared brass) 
sprinkled over the joint, the heat being raised until 
the brass melts and flows into the joint, making a 
union between the pieces. Ordinarily it requires a 
bright-red or dull-yellow heat to melt the brass 
properly. 

Almost any metal that will stand the heat can be 
brazed. Great care must be used when brazing 
cast iron to have the surfaces in contact properly 



IVnSCELLANEOUS WORK. 



185 



cleaned to start with, and then properly protected 
from the oxidizing influences of the air and fire 
while being heated. 

Brass wire, brass filings, or small strips of rolled 
brass may be used in place of the spelter. Brass 
wire in particular is very convenient to use in some 
places, as it can be bent into shape and held in place 
easily. 

A simple brazed joint is illustrated in Fig. 255, 
which shows a flange (in this case a large washer) 
brazed around the end of a pipe. It is not neces- 
sary to use any clamps or wires to hold the work 
together, as the joint may be made tight enough to 
hold the pieces in place. The joint should be tight 
enough in spots to hold the pieces together, but 
must be open enough to allow the melted brass to 
run between the two pieces. Where the pipe 
comes in contact with the flange the outside should 
be free from scale and filed bright, the inside of 
the flange being treated in the same way. 




Fig. 255. 




Fig. 256. 



When the pieces have been properly cleaned and 
forced together, a piece of brass wire should be 
bent around the pipe at the joint, as shown in Fig. 
256, and the work laid on the fire with the flange 



1 86 FORGE-PRACTICE. 

down. The fire should be a clean bright bed of 
coals. As soon as the work is in the fire the joint 
should be sprinkled with the flux; in fact, it is a 
good plan to put on some of the flux before putting 
the work in the fire. Ordinary borax can be used 
as a flux, although a mixture of about three parts 
borax and one part sal ammoniac seems to give 
much better results. 

The heat should be gradually raised until the 
brass melts and runs all around and into the joint, 
when the piece should be lifted from the fire. 

The brazing could be done with spelter in place 
of the brass wire. If spelter were to be used the 
piece would be laid on the fire and the joint cov- 
ered with the flux as before. As soon as the flux 
starts to melt, the spelter mixed with a large 
amount of flux is spread on the joint and melted 
down as the brass wire was before. For placing 
the spelter when brazing it is convenient to have a 
sort of a long-handled spoon. This is easily made 
by taking a strip of iron about f " X }" three or four 
feet long and hollowing one end slightly with the 
pene end of the hammer. 

There are several grades of spelter which melt at 
different heats. Soft spelter melts at a lower heat than 
hard spelter, but does not make as strong a joint. 

Spelter is simply brass prepared for brazing in 
small flakes and can be bought ready for use. The 
following way has been recommended for the prep- 
aration of spelter: Soft brass is melted in a ladle 
and poured into a bucket filled with water having 
in it finely chopped straw, the water being given a 



MISCELLANEOUS WOEX. 



187 



swirling motion before pouring in the brass. The 
brass settles to the bottom in small particles. Care 
must be taken when melting the brass not to burn 
out the zinc. To avoid this, cover the metal in 
ladle with powdered charcoal or coal. When the 
zinc begins to burn it gives a brilliant flame and 
dense white smoke, leaving a deposit of white oxide 
of zinc. 

Another example of brazing is the T shown in 



(G> 







Fig. 257. 

Fig. 257. Here two pipes are to be brazed to each 
other in the form of an inverted T. 

A clamp must be used to hold the pieces in proper 
position while brazing, as one pipe is simply stuck 
on the outside of the 
other. A simple 
clamp is shown in Fig. 
258 consisting of a 
piece of flat iron hav- 
ing one hole near each 
end to receive the two 
small bolts, as illus- 
trated. This strip lies 

across the end of the 

r • .1 1 , Fig. 258. 

pipe lormmg the short 

stem of the T, and the bent ends of the bolts hook 



igg FORGE-PRACTICE. 

into the ends of the bottom pipe. The whole is held 
together by tightening down on the nuts. 

The brazing needs no particular description, as 
the spelter or wire is laid on the joint and melted 
into place as before. 

A piece of this kind serves as a good illustration of 
the strength of a brazed joint. If a well-made 
joint of this kind be hammered apart, the short 
limb will sometimes tear out or pull off a section of 
the longer pipe, showing the braze to be almost as 
strong as the pipe. 

When using borax as a flux the melted scale 
should be cleaned (or scraped) from the work while 
still red-hot, as the borax when cold makes a hard, 
glassy scale which can hardly be touched with a 
file. The cleaning may be easily done by plunging 
the brazed piece, while still red-hot," into water. 
On small work the cleaning is very thoroughly done 
if the piece, while still red-hot, is dipped into melted 
cyanide of potassium and then instantly plunged 
into water. If allowed to remain in the cyanide 
many seconds the brass will be eaten off and the 
brazing destroyed. 

It is not always necessary when brazing wrought 
iron or steel to have the joint thoroughly cleaned; 
for careful work the parts to be brazed together 
should be bright and clean, but for rough work the 
pieces are sometimes brazed without any preparation 
whatever other than scraping off any loose dirt or scale. 

Pipe-bending. — There is one simple fact about 
pipe-bending which, if always carried in mind, 
makes it comparatively easy. 



MISCELLANEOUS WORK. 



189 



Let the full lines in Fig. 259 represent a cross- 
section of a piece of pipe before bending. Now 
suppose the pipe be heated and an attempt made 
to bend it without taking any precautions what- 





FlG. 259. 



llG. 260. 



ever. The concave side of the pipe will flatten 
down against the outside of the curve, leaving the 
cross-section something as shown by the dotted 
lines; that is, the top and bottom of the pipe will 
be forced together, while the sides will be pushed 
apart. In other words, the pipe collapses. 

If the sides can be prevented from bulging out 
while being bent it will stop the flattening together 
of the top and bottom. A simple w^ay of doing 
this is to bend the pipe between two fiat plates held 
the same distance apart as the outside diameter of 
the pipe ^Fig. 260). Pipe can sometimes be bent 
in a vise in this way, the jaws of the vise taking 
the place of the flat plates mentioned above. 

Large pipe may be bent something in the follow- 
ing way: If the pipe is long and hea\^ the part to 
be bent should be heated, and then while one end is 



I go 



FORGE-PRACTICE. 



supported, the other end is dropped repeatedly on 
the floor. The weight of the pipe will cause it to 
bend in the heated part. Fig. 261 illustrates this, 




Fig. 261. 

•the solid lines showing the pipe as it is held before 
dropping and the dotted lines the shape it takes as 
it is dropped. 

As the pipe bends the sides, of course, bulge out, 
and the top and bottom tend to flatten together; 
but this is remedied by laying the pipe flat and 
driving the bulging sides together with a flatter. 

Another way of bending is to put the end of the 
pipe in one of the holes of a heavy swage-block (as 
illustrated in Fig. 262), the bend then being made 




Fig. 262. 

by pulling over the free end. The same precau- 
tion must, of course, be taken as when bending in 
other ways. 

The fact that by preventing the sides of the pipe 
from bulging it may be made to retain its proper 



MISCELLANEOUS WORK. 



191 



shape is particularly valuable when several pieces 
are to be bent just alike. In this case a jig is made 
which consists of two side plates, to prevent the 
sides of the pipe from bulging, and a block between 
these plates to give the proper shape to the curve. 
A piece of bent pipe which was formed in this 




Fig. 263. 

way is shown in Fig. 263, together with the jig 
used for bending it. 

The pipe was regular one-quarter-inch gas-pipe. 
The jig was made as follows: The sides were made 
of two pieces of board about i^' thick. Between 
these sides was a board, A, sawed to the shape of 
the inside curv^e of the bent pipe. This piece w^as 
slightly thicker than the outside diameter of the 
pipe (about '/j,'' being added for clearance). The 
inside face of the sides and the edge of the block A 
were protected from the red-hot pipe by a thin 
sheet of iron tacked to them. 

A bending lever was made by bending a piece of 
|"Xi" stock into the shape of the outside of the 
pipe. This lever was held in place by a ^" bolt 
passing through the sides of the jig, as shown. 



ig2 



FORGE-PRACTICE. 



To bend the pipe it was heated to a yellow heat, 
put in the jig as indicated by the dotted lines and 
the lever pulled over, forcing the hot pipe to take 
the form of the block. 

A jig of this sort is easily and cheaply made and 
gives good service, although it is necessary some- 
times to throw a little water on the sides to prevent 
them from burning. 

Another common way of bending is to fill the 
pipe with sand. One end of the pipe to be bent is 
plugged either with a cap or a wooden plug driven 
in tightly. The pipe is filled full of sand and the 
other end closed up tight. The pipe may then be 
heated and bent into shape. It is necessary to have 
the pipe full of sand or it will do very little good. 

For very thin pipe the best thing is to fill with 
raielted rosin. This, of course, can only be used 
when the tubing or pipe is very thin and is bent 
cold, as heating the pipe would cause the rosin to 
run out. 

Thin copper tubing may be bent in this way. 

A quite common form of pipe-bending jig is 
illustrated in Fig. 264. 

The outside edge of the semicircular casting has 
a groove in it that just fits half-way round the pipe. 
The small wheel attached to the lever has a cor- 
responding groove on its edge. When the tw^o are 
in the position shown the hole left between them 
is the same shape and size as the cross-section of 
the pipe. 

To bend the pipe, the lever is swung to the ex- 
treme left, the end of the heated pipe inserted in 



MISCELLANEOUS WORK. 



193 



the catch at .4 (which has a hole in it the same size 
as the pipe), and the lever pulled back to the right, 
bending the pipe as it goes. 

The stem on the lower edge of the casting was 




Fig. 264. 



made to fit in a vise, where the jig was held while 
in operation. 

Annealing Copper and Brass. — Brass or copper 
may be softened or annealed by heating the metal 
to a red heat and cooling suddenly in cold water, 
copper being annealed in the same way that steel is 
hardened. Copper annealed this way is left very 
soft, somewhat like lead. Hammering copper or 
brass causes it to harden and become springy. 
When working brass or copper, if much bending or 
hammering is done, the metal should be annealed 
frequently. 



194 rORGE-PRACTICE. 

Bending Cast Iron. — It is sometimes necessary to 
straighten castings which have become warped or 
twisted. This may be done to some extent by 
heating the iron and bending into the desired shape. 
The part to be bent should be heated to what might 
be described as a dull-yellow heat. The bending is 
done by gradually applying pressure, not by blows. 
For light work two pairs of tongs should give about 
the right amount of leverage for twisting and bend- 
ing. 

When properly handled (very "gingerly"), thin 
castings may be bent to a considerable extent. 
Before attempting any critical work some experi- 
menting should be done on a piece of scrap to deter- 
mine at just what heat the iron will work to the 
best advantage, and how much bending it will 
stand without breaking. 



HEAT TREATMENT OF STEEL. 

This important subject is receiving a great deal of 
attention in all up-to-date manufacturing plants 
whose output receives, when in use, any unusual 
strains demanding conditions that are not manifest 
in steel treated by ordinary methods. The subject 
covers the processes of heating for forging, annealing, 
hardening and tempering and various modifications 
of the processes mentioned. 

The most important factor is the maii that does the 
work, or who supervises it. Many claims are made 
by men selling furnaces, heat-recording instruments 
and the various paraphernalia used in a heat-treating 



MISCELLANEOUS WORK. 1 95 

plant as to the possibilities to be obtained when 
using the articles they sell. Many of these are desir- 
able, some are indispensable. But best results can- 
not be obtained unless they are used by a "good" 
man. There is no furnace, pyrometer or other part 
of the equipment of a heat-treating plant made that 
will take the place of brains. In fact, the better the 
equipment, the better the man needed in order to get 
maximum results. 

To obtain best results when heat-treating steel the 
workman must understand the metal he is working 
on. There is no valid excuse at the present time for 
a man engaged in any of the processes of heat- 
treating steel not having a working knowledge of the 
subject. He should know how it is made, what ele- 
ments go into its composition, what effect each of 
these has upon the steel, the effect of varying per- 
centages, and how the presence of certain elements 
may modify the effect of others. The effect of vari- 
ous temperatures on steel of different analyses and 
the effect of cooling heated steel at different time 
rates should be understood. While a long experi- 
ence in this particular line of business is a valuable 
asset to any man, it does not enable him to suc- 
cessfully handle tools and steels that he is not famil- 
iar with. 

Twenty-five years ago there was comparatively 
little literature devoted to this subject. To-day 
there are many excellent books to be had. Some are 
of particular value to the graduate metallurgist but 
of little use to the practical man of ordinary educa- 
tion, others are so written that they are of value to 



ig6 rORGE-PRACTICE. 

both, while still others are intended for the man 
who is devoting his time to the actual processes in- 
volved in the practical operations in the heat- 
treating room. 

The workman should not be content with the 
study of the latter alone as he will never understand 
the subject as he should until he knows the metal he 
is treating. Space prevents our taking up the study 
of the making of steel, or to any great extent the 
influence of the elements, but the writer wishes to 
urge on every reader, and on every man engaged 
in heat-treating steel the necessity of a thorough 
study of steel in order that he may know how to best 
apply the information given in this, and other books 
written especially for the practical man. 

Steel is affected by heat to a greater degree than is 
generally understood Reference to any one of a 
number of handbooks will convince one of the truth- 
fulness of this statement. In the table of "Co- 
efficients of the Expansion of Solids" is found the 
amount steel expands per degree of heat absorbed. 
Reason dictates that if the metal is expanded by 
heat the various portions should be heated as uni- 
formly as possible in order that uneven expansion 
does not take place, because if one portion is heated 
more than another strains are set up. These strains 
tend to weaken or rupture the steel. If these strains do 
not manifest themselves at the time the piece is un- 
evenly heated they will during subsequent treatment. 

While it is necessary to uniformly heat steel to 
avoid the trouble just mentioned, long exposure of 
the metal to high heats, especially if it contains con- 



MISCELLANEOUS WORK. I97 

siderable carbon tends to weaken it. Knowledge 
gained by experience enables the operator to so apply 
heat that the desired uniform temperature may be 
obtained with the minimum of weakness due to 
either strains or long heats. 

Steel that has been heated for forging, annealing, 
hardening or any of the other processes involved in 
heat treating must be cooled. The method and 
rapidity of cooling has a pronounced effect on the 
metal. The writer's attention was called to a batch 
of forgings that could not be machined on account 
of hardness. Investigation showed that previous 
batches which had machined easily had been placed 
in an iron box, in the bottom of which was a quantity 
of hot ashes. These forgings were placed in the box 
while red hot. The repeated addition of forgings as 
they left the drop hammer prevented rapid cooling, 
thus insuring a condition that made machining an 
easy matter. This box was so located that no mois- 
ture or drafts of air could reach it. The forgings 
under consideration were made from steel of the 
same analysis as former batches, but the work was 
done by a "new man" and thrown while red hot 
onto a floor of damp earth, with the result that por- 
tions of many of the pieces were partially hardened, 
thus rendering machining impossible until they were 
annealed. The cost of annealing, plus that of milling 
cutters spoiled in the attempt to machine the pieces, 
made the cost of that particular lot greatly in excess 
of what it should have been. 

In some lines of work, especially that branch 
devoted to the making of guns of certain types, and 



igS FORGE-PRACTICE. 

munitions, certain portions of the product are given 
a degree of hardness before the finish machining 
operations. While it is common practice in many- 
shops to harden pieces before finishing and then 
bring them to size by grinding the operations referred 
to above are accompHshed by means of cutting tools. 
This practice makes necessary a very exact knowl- 
edge of the desirable methods of treating both the 
product and the cutting tools used. Exact tempera- 
tures and time exposures to heat are essential, and 
as these vary somewhat according to the composi- 
tion of the steel used intelligently conducted experi- 
ments aided by accurate heat determining instru- 
ments are necessary. 

Annealing, while primarily a softening process, 
has been extended so as to produce certain desirable 
qualities not possessed by the steel as furnished by 
the mills. 

Forgings and other articles are many times 
strengthened and toughened to a degree not dreamed 
of by anyone twenty-five or thirty years ago. 
These results are directly traceable to the efforts of 
men who are thoroughly familiar with the nature 
and composition of steel and the effects of heat on 
its structure and strength. The credit for much of 
this knowledge belongs to some of our leading 
metallurgists coupled with the efforts of practical men. 

While a technical education specialized along the 
lines under consideration is highly desirable, any 
man of ordinary education and intelligence can by 
diligent study and practice acquire a knowledge of 
the subject of Steel and Its Heat Treatment that 



MISCELLANEOUS WORK. 1 99 

will be of inestimable value to himself and others. 
The day has passed when some one man who was 
supposed to "know it all," or who by the applica- 
tion of some secret powder, or other concoction 
could do the supposedly impossible, and who, as a 
result, could dictate the running of this branch of 
the business. There is a reason for everything, and 
when one knows the reason he is able to meet almost 
any emergency. 

Steel. — The word "steel" conveys very little 
meaning to the man who is famihar with the compo- 
sition of the various alloys of iron usually grouped 
under this heading. We often hear the terms open- 
hearth steel, Bessemer steel, crucible steel, high steel, 
low steel, hard steel, soft steel, alloy steel, etc. A 
term often used and which means very little is 
machine steel, or machinery steel as it is sometimes 
called. The so-called machine steel may contain 
very little carbon, or it may have a fairly high per- 
centage. In the first case it would be soft and com- 
paratively weak, while, in the latter, it would be 
much harder and stronger under a steadily applied 
load. Under ordinary circumstances both would be 
tagged "machine steel" whether made by either the 
Bessemer or the open-hearth process, provided it was 
to be used in making parts of machines, implements, 
etc. 

An intelligent study of the subject will show that 
steels of various compositions are made to meet 
varying demands. In ordinary steels the element 
present to give strength, or to make hardening of 
the metal possible, is carbon, and as this element is 



200 FORGE-PRACTICE. 

used to give the desired condition men familiar with 
the metal usually distinguish it by the carbon con- 
tent. The term "percentage of carbon" is used by 
many while others state the amount in "points." 
A point is one one-hundredth part of one per cent of 
any element that goes into the composition of iron 
or steel. A 40-point carbon steel contains 0.40 per 
cent carbon. In speaking of this steel one would 
say 40-point carbon steel, or to per cent carbon steel. 
If it was made by the open-hearth process it would 
be spoken of as 40-point, or to per cent, open-hearth 
steel; if made by the Bessemer process it would 
be called 40-point, or to per cent, Bessemer steel. 

The product of the Bessemer converter and of the 
open-hearth furnace having the same carbon con- 
tent may be similar in most respects, or they may be 
widely different. As the time consumed in running 
a charge in the converter is much less than the neces- 
sary time in the open-hearth furnace the product is 
more liable to be variable. 

There are two types of Bessemer converters and 
the same number of open-hearth furnaces, namely the , 
acid and basic, and the product of each is known as 
acid steel or basic steel. Very little, if any basic 
Bessemer steel is made in the United States, while 
both acid and basic open-hearth steels are produced 
here. Knowing these facts one is able to designate 
a steel very accurately by stating the kind and car- 
bon content; as, 60-point carbon basic open-hearth 
steel. Under ordinary conditions the percentages 
of other elements entering into the composition con- 
form very nearly to fixed formulas, but where any of 



MISCELLANEOUS WORK. 20I 

these vary to any degree in order to produce some 
desired result, the content of these elements is stated 
also. 

The custom prevailing in some shops of ordering 
so many feet of machine steel is to be discouraged, 
for, while this term may have some specific meaning 
with the steel manufacturer, it has little or none 
with the average mechanic, purchasing agent, manu- 
facturer or man employed in a steel warehouse. 
The receiving of stock ordered in this way and then 
of storing it in a common rack has been, and is a 
source of unsatisfactory product and serious loss to 
many concerns. 

As Jew kinds and grades of steel as is consistent 
with good results should be used in any one plant 
unless those in charge have a working knowledge of 
steel, and closely follow the various kinds and grades, 
and see that they are marked or tagged so they can 
be readily distinguished, as otherwise endless con- 
fusion will result. 

The purchase of Bessemer steel for any purpose 
where a uniform analysis is necessary, or where it is 
to be hardened or case hardened is not to be recom- 
mended unless all stock received is to be subjected 
to chemical analysis and physical tests. Even when 
these precautions are observed the various bars in a 
shipment are liable to vary in analysis to an extent 
that will cause serious trouble. For this reason the 
use of the product of the acid Bessemer converter 
is to be discouraged where the product is to be hard- 
ened or where it is to be subjected to shock or inter- 
mittent strains of any sort. 



202 FORGE-PRACTICE. 

If acid open-hearth steel is to be case hardened, 
and especially if the carburizer to be used is raw 
bone, the phosphorus content in the steel should be 
low as the effect of phosphorus, if present in more 
than allowable percentages, is to produce brittleness 
under any but a steady load. For the reasons men- 
tioned it is generally safer to use basic open-hearth 
steel where the product is to be hardened in any way. 
These statements are intended to apply to plants 
whose size do not warrant the employing of a chem- 
ist, and where the purchaser must rely on the steel 
warehouse for its product. 

Most steel mills will, on request, give an analysis 
best suited to a given purpose, if a description of the 
work to be made together with the physical strains 
it is to receive in use are stated. 

Alloy Steels. — In order to obtain the maximum of 
strength without increasing the size of the piece, 
various elements are used in connection with the 
carbon. Certain of these elements reduce the ten- 
dency to break from repeated stresses and vibration 
thus increasing the life of the article. Such steels 
require heat treatment because in the natural or 
annealed state they are little, if any, better than 
plain carbon steels. When properly heat treated 
they show a decided improvement in physical char- 
acteristics. 

Nickel Steel. — Nickel steel containing 0.15 per cent 
carbon is used for parts that are to be case hardened 
and which require a very hard suiface with a tough 
strong interior, or core. It is especially suited for 
gears that are to be case hardened. That containing 



MISCELLANEOUS WORK. • 203 

0.20 to 0.25 per cent is also used for pieces that re- 
quire case hardening, but the process must be adapted 
to the increase of carbon. If properly treated the 
core will be stronger than if a lower carbon steel was 
used. 

Nickel steel with 0.30 to 0.35 per cent carbon is 
used, at times, for parts that are case hardened but 
is not to be recommended. It is especially valuable 
for such parts as automobile driving shafts, crank 
shafts, axles, etc. The particular heat treatment 
necessary to produce desired results depends on the 
requirements of the individual piece. Wide varia- 
tions as to the ultimate strength and elastic limit are 
obtained by using various quenching mediums, and 
by variations in temper drawings. 

Nickel-chromium Steels.— Steel containing nickel 
and chromium in combination with carbon is used. 
The percentage of these elements varies according 
to the requirements of the piece. For use in making 
gears that are to be oil hardened the carbon content 
is about 0.5 per cent, while, for those requiring case 
hardening it is about 0.25 per cent. The amount of 
nickel varies from i to 3 . 5 per cent and the chromium 
from .3 to 1.5 per cent. 

Chrome-vanadium Steels. — Chrome-vanadium steel 
with a low carbon content is used for parts that 
require case hardening, and the carbon should not 
exceed 0.20 per cent. The 0.40 to 0.45 per cent 
carbon steel is used where great strength together 
with toughness is required. It is extensively used 
for gears, springs and other articles that are to be 
quenched in oil. 



204 FORGE-PRACTICE. 

Tool Steel. — By the term "tool steel" we mean the 
product of the crucible process made especially for 
cutting-tool purposes. However, a large amount of 
crucible tool steel is used in making parts of ma- 
chines, etc., and many times it is used where a good 
grade of open-hearth steel would answer the purpose 
as well and at a lower cost. On the other hand, con- 
siderable high carbon open-hearth steel is used for 
cutting and other tools. Notwithstanding its lower 
initial cost its use is not to be advocated unless those 
in charge have a knowledge of the subject that makes 
it possible for them to rightly decide as to what tools 
it is suitable for. When one considers that many dol- 
lars' worth of labor may be expended on a tool the 
steel in which costs but comparatively little, it is ap- 
parent that saving on steel may be costly "economy." 
However, if a "cheap" steel will answer the purpose 
as well it is folly to buy a high-priced article, espe- 
cially where it is used in large quantities. High 
price does not always mean adaptability. A steel 
may cost many times as much as another that is far 
better suited for a given purpose. The essential 
thing to consider is the fitness of the steel for the 
purpose for which it is to be used. When the right 
steel is to be had it should be procured regardless of 
cost. 

Tool steel is made with a great range of carbon 
content. Where it is to be subjected to battering 
action, or other severe usage, and is to do no cutting, 
the carbon runs from 0.60 to 0.70 per cent, while, for 
cutting tools requiring extreme hardness it may be 
1.60 per cent or even higher. The varioT's per- 



MISCELLANEOUS WORK. 205 

centages between these extremes are adapted for 
most tools used in cutting, pressing, bending and the 
various other processes involved in working metals 
into marketable condition. 

The high-carbon steels require extreme care in 
the various heat-treating processes, and their use 
is discouraged by some on this account. The argu- 
ments advanced against its use appear to a skilled 
man without foundation, because men skilled in this 
branch of work can be had if they are given the 
necessary inducements. 

The higher the carbon the lower the critical point 
of the steel. If the operator bears this fact in mind 
he will have no trouble in determining the proper 
heats to employ in forging, annealing and hardening 
high-carbon steel. The idea entertained by some 
manufacturers that they must use a steel that fits 
the ability of their employees seems to be without 
proper foundation. It is better to use steel suited 
to requirements, and then employ workmen capable 
of properly treating it. 

The percentage of carbon is many times denoted 
by the term "temper." When used in this con- 
nection it has no association with the "letting down" 
process known as drawing the temper after harden- 
ing. The following table gives the uses of steel of 
various carbon contents as adopted by at least one 
manufacturing concern, and conforms very closely 
to general usage. It cannot be regarded as abso- 
lutely correct under all conditions, but answers as 
an approximate guide. 



2o6 rORGE-PRACTICE. 

Percentage t, , 

of Carbon. Tools. 

1.60 Tools requiring extreme hardness where toughness 
is not essential, for cutting partially hardened 
forgings, etc. 

1.50 Turning hard metals, turning chilled rolls, etc. 

1.40 Turning hard metals, corrugating tools, brass working 
tools and where a fine edge is required in connec- 
tion with light cuts. 

1.30 General tools for lathe work, cold trimming dies, cutting 
dies. 

1.20 This is the steel used more than any other for general 
cutting tool purposes, jewelers' rolls, small taps, 
twist drills, milling cutters for ordinary cuts, punch 
press dies, dinking dies, screw threading dies. 

1. 10 Taps in general, axes, saws, wood-working tools, 
milling cutters for rough usage, small punches, 
reamers, broaches. 

1. 00 Large milling cutters, drifts, swages, springs. 
.90 Cold dropping dies, cold chisels, hand-driven punches, 
punch-press dies and punches to be subjected to 
rough usage, large milling cutters to be pack 
hardened. 
.80 Shear knives, blacksmiths' cold chisels, hammers, 
sledges, tack chisels, boiler-makers' tools, hammer 
dies, masons' tools. 
.70 Blacksmiths' tools in general, hot drifts, hot sets, track 

tools. 
.60 Tools to be used for hot work to stand battering, drop 
forging dies for hot work, hot trimming dies, 
flatters, fullers, hot swages. 
.50 Striking up dies for hot work that are water cooled. 

While the table gives a general idea of the adapta- 
bility of steels of various carbons it is necessary 
many times to use different grades to accomplish 
some desired result. For instance, 1.20 per cent 
carbon steel is recommended for the ordinary run of 
taps, yet taps used for sizing a hole already threaded 
and where but a very small amount of stock is to be 
removed are many times made from 1.40 per cent 
carbon steel as it will retain its size much longer. 
Small milling cutters that take light cuts on pieces of 
irregular form are sometimes made from 1.40 per 
cent carbon steel. The use of higher carbons than 



MISCELLANEOUS WORK. 207 

those specified require the exercise of extreme care in 
heating and quenching, but the results obtained 
warrant the extra care and expense. 

Light in the Hardening Room. — The degree of light 
allowable in a heat-treating room is of vital impor- 
tance, and the ideas of men engaged in the various 
branches of the business do not always coincide. 
The writer has visited shops where the rooms de- 
voted to this work were absolutely dark except for 
an individual incandescent light here and there, 
but these so located that they did not cast any rays 
toward any heating furnace. He has been in plants 
where the furnaces were located in rooms whose walls 
and ceilings were a mass of glass, allowing strong, 
direct light free access to every portion of the room. 
The former condition is far preferable to the latter 
so far as ability to discern heats is concerned, but 
objectionable from the standpoint of the workman's 
health. 

A heat-treating room should be dry and well ven- 
tilated, and should be, so far as possible, a comfort- 
able place to work in, but the lighting system should 
be so arranged that no direct or strong light can 
enter it, and the light throughout the room should be 
as uniform as possible. A workman engaged at a 
furnace observing heats finds himself handicapped 
if when he looks away from his furnace he finds 
that his eyes encounter a strong light in some other 
part of the room. When he looks back at his work 
it is several seconds before his eyes adjust them- 
selves to the change. It might appear to one not 
intimately conversant with the heat-treating prob- 



2o8 FORGE-PRACTICE. 

lem that the increasing use of heat-measuring in- 
struments and systematic methods of treating steel 
now employed that the eye was being less relied on 
than formerly, such is not the case. The pyrometer 
and the systematic time systems so successfully 
employed are really only aids to the workman. The 
human element is more important than ever under 
the conditions that prevail, and their importance 
will increase as conditions become better systema- 
tized. It is always a mistake to think that any 
system or instrument can take the place of brains. 
They are wonderful helps, but never substitutes. 

The lighting of the room under consideration 
should be scientifically planned. A diffused light 
that is as constant as possible should be obtained. 
The exact degree of light that will give the best 
results cannot be arbitrarily stated, but should be 
so adjusted as to give best results. The aim in a 
number of places is to get a constant light approach- 
ing as nearly as possible what is known as twilight. 

The advantage claimed for the totally dark room 
is that the light is absolutely constant. This is true, 
but the many disadvantages resulting from this con- 
dition seems to outweigh the resulting good. 

Where but one small furnace is used in a plant, it 
is customary to locate it in a spot that is not wanted 
for anything else, regardless of the fitness of the loca- 
tion. It is necessary many times to place a furnace 
in a room with the regular metal cutting machines 
that require a good, strong direct light. Under such 
circumstances it should be placed where it will get 
the least possible amount of this light, or if this is 



MISCELLANEOUS WORK. 209 

not possible devise some way of shutting the light off 
so it cannot strike the furnace or into it, or into the 
workman's eyes. Thousands of tools are ruined each 
year because this precaution is not taken. 

Heating Furnaces. — Under this heading we will con- 
sider the various forms of heating devices used in 
the ordinary hardening room. The blacksmith's 
forge while not exactly a furnace is used very exten- 
sively in heating steel for forging and hardening. 
Where many pieces of a kind are to be heated its 
use is not to be advocated, as some form of furnace 
having, an enclosed heating chamber is generally 
preferable, but where but few pieces of a given size 
and form are to be treated, and these to be followed 
by others of various design a large, clean fire pro- 
vides a very satisfactory means of heating. 

Muffle Furnaces. — Muffle furnaces were at one 
time very extensively used in heating steel for hard- 
ening. The work was placed in a muffle, or cham- 
ber, so constructed that the products of combustion 
could not come in contact with the pieces being 
heated. As a result oxidation of the surfaces was 
practically eliminated. As the heating is done 
entirely by radiation the cost of fuel is greatly in 
excess of a furnace where the flame comes in direct 
contact with the work. For certain kinds of work 
especially small pieces and those of intricate shape 
the muffle furnace provides an ideal means of 
heating. 

Semi-muffle Furnaces. — In this type a chamber is 
provided for the w^ork, and the flame circulates 
around the walls for a distance and then enters the 



2IO FORGE-PRACTICE. 

chamber. The mixture of fuel flame, and air is so 
regulated that perfect combustion takes place before 
it comes in contact with the work. This type of 
furnace is very satisfactory for most classes of work 
when heating for annealing, hardening, etc. 

Direct Flame Furnaces. — In heating for forging, and 
where the steel is enclosed in boxes when heating for 
case hardening and the various heat-treating opera- 
tions, furnaces are many times constructed so that 
the flame enters directly into the heating chamber, 
thus insuring a very intense heat at a comparatively 
low fuel cost. 

The question often asked is, "What is the best 
type of furnace?" There is no "best" type of fur- 
nace. The kind, size and design should conform to 
the character of the work to be treated. Many 
excellent furnaces are to be obtained from manu- 
facturers who have made a specialty of heat-treating 
apparatus for years. When a furnace that exactly 
meets requirements can be purchased this course is 
to be advocated. Many times furnace manufac- 
turers will design and build a special type or size of 
furnace at a figure that is less than such an article 
can be built for in a shop not especially equipped 
to do such work. ^ At times it is possible to design and 
build a satisfactory furnace in the shop where it is 
to be used, provided those in charge have a thorough 
knowledge of furnace design. 

Furnaces are built so that the fuel gases and blast 
enter at variously located openings and the advisa- 
bility of any particular design must necessarily 
depend on the character of the work and the results 



MISCELLANEOUS WORK. 211 

desired. Fig. 265 shows an under-fired furnace, the 
gases entering at the bottom as shown. The gas 
and air uniting in the combustion chamber and rising 
to the roof, and are then forced down onto the floor 
of the furnace. In this particular furnace there are 
no walls extending up from the floor. If work is 
placed very near the edge, excessive heating of the 
portions nearest the rising gases is almost sure to 
result. 





Fig. 265. 



Fig. 266. 



Fig. 266 shows a design identical with Fig. 265 ex- 
cept that upright walls are added, to prevent the 
undesirable results mentioned. The height of these 
walls is not material so long as they are high enough 
to prevent uneven heating, and yet not sufficiently 
high to prevent the gases flowing naturally into the 
chamber. If carried too high the gases are forced 
through the small openings at high velocity and 
impinge against the upper portions of pieces in the 
furnace heating them hotter than the balance, this is 
especially true of large pieces that extend up weU 
toward the roof. 



212 



FORGE-PRACTICE, 



Top-fired Furnaces. — Where the work is encased 
in boxes or tubes top-fired furnaces are many times 
used. The floor should be thoroughly perforated 
or made up of grates or bars, or the bottom portions 
of boxes, or articles being heated will be much cooler 




Fig. 267. 

than the tops. Such furnaces properly designed and 
intelligently operated give good results at a compara- 
tively low fuel cost. Although if unprotected pieces, 
such as dies, etc., are to be heated it is doubtful if as 
good results will be obtained as with an underfired 
furnace. 



MISCELLANEOUS WORK. 



213 



Fig. 267 shows a small furnace used in heating com- 
paratively small pieces. The fuel used is illumi- 
nating gas. For all around work up to the capacity 
of the furnace this is a very satisfactory type. Fig. 268 
shows a furnace designed for heating reamers and 
other long and comparatively slender articles. As 




Fig. 268. 



these pieces are suspended from the top there is little 
danger of their springing when heating. A coke 
burning furnace is shown in Fig. 269. For certain 
purposes this furnace is very satisfactory. It is an 
especially desirable type for use in heating high- 
speed steel for forging. 

Fuel. — Various forms of fuel are used in heating 
furnaces. Among the commonly used forms are 



214 



FORGE-PRACTICE. 



anthracite (hard) coal, bituminous (soft) coal, coke, 
charcoal, illuminating gas, producer gas, fuel oil, 
kerosene and gasoline. The advisability of using 
any certain kind depends on the character of the fur- 
nace, the nature of the work to be heated, and the 
locality of the factory. 




Fig. 269. 



In certain parts of the country a particular form of 
fuel may be difficult to get, or too expensive to use. 
Where illuminating gas can be obtained cheaply 
we have a very satisfactory means of heating small 
furnaces. Where fuel oil can be easily obtained at 
a reasonable cost we have one of the very best means 
of heating large furnaces, and it also works well for 
small furnaces provided they are equipped with 
suitable burners. 



MISCELLANEOUS WORK. 215 

Kerosene and gasoline are sometimes used as fuel. 
The cost of this fuel, however, is apt to be greatly in 
excess of fuel oil. Charcoal is used in the black- 
smith's forge for heating tool steel, while coke is quite 
extensively used in small furnaces of different types. 
Both anthracite and bituminous coal are used in large 
and small furnaces where the steel does not come in 
direct contact with the fuel. 

Some large plants are provided with gas producers 
used in making gas for heating purposes. Furnaces 
equipped to burn illuminating gas can be run on 
this fuel at a small cost. 

Small furnaces are usually made of a height that 
allows a man of ordinary stature to observe the 
interior of the heating chamber without any special 
exertion. Large furnaces, if used for pieces or boxes 
of ordinary size are made so that the floor of the fur- 
nace is about 2 feet above the floor level of the room, 
in order that boxes may be placed in the furnace 
easily. While those intended for heating extra 
heavy pieces have the floor on the same level as the 
room floor, the boxes being run in on a truck of the 
design shown in Fig. 270. 

To describe the ideal furnace for all around pur- 
poses would be impossible, as the character of the 
work to be heated, the desired results and the fuel 
to be used must all be taken into consideration. The 
writer has in mind a hardening plant having twelve 
large furnaces used in heating steel. Several of 
these are designed for carburizing work for case 
hardening. These are run at temperatures varying 
from 1650° to 1850° F. while others are intended for 



2l6 FORGE-PRACTICE. 

pieces that are to be pack hardened and where 
uniform temperatures not exceeding 1450° F. are 
desired. One furnace is used for pack hardening 
high-speed steel and requires temperatures ranging 
from 1750° to 2250° F. while others are used for all 
around work. Most of these use fuel oil for heating, 
while those used for work requiring the lower tem- 
peratures use hard coal as fuel. Contrary to the 
claims of many furnace men it is found that very 




Fig. 270. 

uniform results, at low temperatures, can be main- 
tained with this fuel, under ordinary conditions. 

Lead Bath. — Lead provides a fairly satisfactory 
method of heating steel. In many shops it has given 
way to various salts which are lighter and do not 
oxidize as readily. However, red hot lead affords a 
very good means of heating if certain precautions are 
observed. Oxidation of the surface may be over- 
come to a degree by keeping it covered with pow- 
dered charcoal. The practice of using any old scrap 



MISCELLANEOUS WORK. 21 7 

lead cannot be too severely condemned, as good 
results can only be obtained by using a brand of pig 
lead known as "commercially pure lead." 

The crucible used to hold the lead should be of 
graphite. The life of graphite crucibles may be very 
materially lengthened by annealing before they are 
used, which is done by placing in a furnace, heating 
to a full red, and then removing and placing on top 
of the furnace, or in some warm place where no cur- 
rent of air can strike them, and left until cool. 

Crucibles may be heated in a coke or coal fire, but 
better results follow the use of specially designed fur- 
naces burning gas or oil as shown in Fig. 271. The 
burners should be so arranged that the flame will 
circulate around the crucible instead of impinging 
against it. A piece of fire brick should be placed 
under it for the crucible to rest on. 

After using and before cooling the lead should be 
poured out of the crucible as the expansion of the 
metal when it is remelted would crack the crucible. 
It is advisable to cast the lead into small blocks, as it 
can be conveniently handled when recharging the 
crucible. 

Melted lead has a tendency to stick to steel unless 
the surface of the piece is coated with some substance. 
There are several dips that are used with more or 
less satisfactory results. A dip commonly used is 
made by dissolving i lb. of ferro-cyanide of potas- 
sium in I gal. of boiling water; when this cools it is 
ready for use. Salt is dissolved in water until a sat- 
urated solution is obtained. A thin paste of rye 
ilour is sometimes used. The following paste has 



2l8 



FORGE-PRACTICE. 



been used by the writer for many years with excel- 
lent results: pulverized charred leather 2 parts, 
table salt 4 parts, wheat flour 3 parts. The ingre- 
dients are well mixed and water is added to the mix- 
ture until it reaches the consistency of varnish. 




Fig. 271. 



After the pieces are immersed in any of the dips 
they should be placed where they will dry quickly. 
This is done many times by placing them on the 
plate on top of the furnace and also serves to pre- 
heat the pieces before they are placed in the lead. 
Moisture of any kind must never be allowed to get 
into the lead or particles will fly, which may produce 



MISCELLANEOUS WORK. 219 

blindness if they enter the eyes. If the paste men- 
tioned is used its fusing point indicates the proper 
temperature at which ordinary carbon tool steels 
are hardened. As steel is lighter than lead articles 
to be heated will float on the surface of the bath 
unless held under the surface. If many pieces are 
being treated much time can be saved by using a 
holder of some form for this purpose. 

Preheating before putting in the lead is necessary 
for pieces having large and small portions adjacent 
to each other. 

A gas-fired furnace equipped with an automatic 
heat controller is shown in Fig. 272. It is claimed by 
the manufacturers that Gas Blast Furnaces operated 
with it will not vary more than 5° F. from a fixed 
temperature to which the instrument is set. 

The instrument consists of two distinct parts: A 
pyrometer, so constructed that the movement of the 
dial pointer both indicates and controls the temper- 
ature, and a pneumatic valve attached to the fur- 
nace operated by the same air pressure supplied to 
the furnace for combustion, admitting both gas and 
air in the correct proportion to maintain the desired 
temperature. 

While such a controller is of but little practical 
value on a furnace doing a variety work in small lots, 
or which are made from varying grades of steel, its 
usefulness where large batches of delicate tools are 
heated can hardly be overestimated. 

Heat-recording Instruments. — Manufacturers are re- 
alizing more and more the importance of proper tem- 
peratures in the heat treatment of steel. Modern 



220 



FORGE-PRACTICE. 



appliances used in testing the hardness of materials 
show that a variation of a few degrees has a pro- 
nounced effect on the condition of the steel. The 




Fig. 272. 



higher the carbon content the more pronounced the 
effect of heat. Tools made from high carbon steels 
and that are to be subjected to excessive strains are 



MISCELLANEOUS WORK. 221 

found to be very much injured, at times, when 
heated above the proper temperature. The writer 
has seen cases where a 1.60 per cent carbon steel 
heated 15° F. above the temperature it should have 
received, was decidedly inferior to that cut from . the 
same bars and heated to the right temperature. 
Some writers claim to have observed like results at 
even slighter variations than noted above. Steel 
that is underheated shows as great, or even greater, 
variations so far as practical results are concerned. 

Knowing that a slight variation in temperature 
leads to undesirable results, and that the human eye 
is not to be absolutely relied upon, it is apparent 
that in order to meet modem requirements articles 
made from high carbon steel must be heated under 
conditions that render it possible to obtain very 
nearly exact temperatures. 

At the present time there are a number of reliable 
pyrometers on the market. Any one of these will 
give desirable results if properly installed and care- 
fully watched. Like all delicate instruments and 
complicated machinery they need frequent inspec- 
tion and careful testing. Pyrometers should be 
calibrated every little while to make sure they are 
recording correctly. The writer knows of one con- 
cern whose chemist tests all pyrometers once a week ; 
in another factory they are tested every other day. 
The frequency with which these tests should be made 
cannot be stated arbitrarily, but they should be 
made whenever, in the judgment of the furnace man, 
everything is not exactly right. 

A man whose eyes are trained to discern heats can 



222 FORGE-PRACTICE. 

tell within a few degrees the temperature in a fur- 
nace, provided it does not exceed 1800° F. if light 
conditions are favorable. If the pyrometer reading 
does not closely correspond to the temperature as 
indicated by practical tests, and results do not tally 
with results obtained by previous treatment under 
the same conditions, no time should be lost in cali- 
brating the instrument. 

The writer's attention was called at one time to a 
large lot of projectiles that were giving considerable 
trouble when machined. These pieces were sup- 
posed to be heated to 1550° F. and quenched in 
a bath of oil, after which they were reheated to 
1000° F, This treatment was given prior to the 
essential machining operations. Chemical analysis 
showed that the various pieces were of practically 
the same composition as former batches that ma- 
chined satisfactorily. Investigation in the heat- 
treating plant showed, according to observation, 
that the temperature of 1550° F. was much ex- 
ceeded. When tested out with ' ' sentinel cones ' ' the 
pyrometer was found to register nearly 200° F. out 
of the way. It was also calibrated in connection 
with a test pyrometer and the amount of variation 
noted substantiated. There is little excuse for any 
such variation as just noted, as the color variation 
should have been apparent to the furnace man no 
matter what the pyrometer readings may have been. 

It is customary in most large plants to have an 
extra pyrometer known as a "test pyrometer" 
whose accuracy is known. This instrument is 
coupled up and used in connection with the regular 



MISCELLANEOUS WORK. 223 

pyrometer and the readings compared. In the 
absence of a test pyrometer sentinel cones may be 
used. These cones are made from earthy and 
metalHc substances and the fusing temperature is 
marked on each cone. It is a good plan to have 
on hand a number of cones of different fusing 
points. 

In making a test a cone of the desired grade is 
placed in the furnace while the temperature is low 
and the heat gradually increased until the cone 
breaks down. At the moment it breaks down note 
the reading of the pyrometer. If the pyrometer 
is used to denote various temperatures a number of 
cones having different fusing points may be placed 
in the furnace at a time, those having the lowest 
and highest fusing points corresponding with the 
range of temperature usually indicated by the pyrom- 
eter. When making these tests it is advisable to 
have two men, one to watch the cones and the other 
the reading of the pyrometer. When a cone crumbles 
the man observing it gives a signal and the other 
notes the reading. 

Sentinel cones are also useful where there are no 
pyrometers. By occasionally placing one, whose 
predetermined fusing point is the same as the tem- 
perature to which the work should be heated, in the 
furnace together with a piece of steel of about the 
size and shape of the cone and gradually raising the 
temperature of the furnace until the cone breaks down. 
The appearance of the steel should be carefully 
noted at the instant the cone crumbles. This prac- 
tice tends to keep fixed in the operator's mind the 



2?4 rORGE-PRACTICE. 

exact temperature to which he should heat the steel 

he is treating to get desired results. 

The writer would not be understood as advocating 
the use of cones when a good pyrometer is available, 
neither would he advise their use in calibrating 
pyrometers when it is possible to obtain another 
instrument of known reliability, but in the absence 
of these the cones may be made to answer. 

Pure salt may be used in testing pyrometer read- 
ings. Insert the thermo-couple in a small crucible 
containing pure salt and heat the salt to 1600° F. 
Remove the crucible from the furnace and allow it to 
cool. At the freezing point of salt, which is 1472° F. 
or 800° C, note the pyrometer reading. When the 
salt is cooled to the freezing point the temperature 
remains fairly constant for a short time, after which 
the cooling down to normal is fairly uniform. 

The melting point of several different metals may 
be satisfactorily employed for checking pyrometers. 
The melting points of those most generally used for 
this purpose are as follows : 

Tin 450° F. 

Zinc 787^^ F. 

Silver 1761° F. 

In many cases each furnace is provided with a 
pyrometer, while under different conditions a num- 
ber of furnaces are connected to one pyrometer, each 
furnace reading being obtained by means of a switch. 
When working under the latter condition each fur- 
nace must be numbered and the switch thrown to a 
pole corresponding to the number of the furnace 



MISCELLANEOUS WORK. 



225 



whose temperature is to be read. Such a switch- 
board is shown in Fig. 273. 

In some large heat-treating plants a central pyrom- 
eter is maintained ; this is connected with the various 
furnaces, and is in charge of an operator who, by- 
means of various colored lights located on each fur- 
nace, signals the furnace 
man regarding his heats. 
Three electric lights are 
on each furnace. The red 
light burns when the temp- 
erature is too low, the white 
light when the tempera- 
ture is within the accepted 
limits, and the green light 
when the temperature is 
too high. 

Fig. 274 shows an Auto- 
matic Signaling Equipment 
which is attached to the 
furnace and is directly con- 
trolled by the furnace temperature, 
with the central pyrometer. 

In Fig. 275 is shown a thermo-couple immersed in a 
pot of molten lead. The application is the same if 
other metals, or salts are used in the bath. 

In many large plants where the amount of work 
warrants the outlay recording pyrometers are in- 
stalled in the office of the superintendent, or other 
official. These instruments indicate and record the 
furnace temperatures, whereby it is possible for those 
in charge to keep records of the temperatures. 




Fig. 273. 



This does away 



226 



FORGE-PRACTICE. 



Baths. — There are many forms of baths used in 
hardening, and an almost endless number of liquids 




Fig. 274. 

and mixtures for cooling. The particular form 
desirable depends on the nature of the work to be 
cooled. 




Fig. 275. 



A pail, barrel, or tank answers very well for many 
kinds of work, and is entirely unsuited for others. 
Where but a few small pieces are to be hardened a 



MISCELLANEOUS WORK. 



227 




Fig. 276. 



small vessel may be used, but larger pieces require a 
generous quantity of liquid to do away with change 
of temperature. Where many 
pieces are to be done in succession 
some means must be provided to 
keep the bath at an even temp- 
erature. At other times it is 
necessary to project the liquid 
against some certain portion of 
the piece. 

A common form of bath hav- 
ing a jet coming up from the 
bottom is shown in Fig. 276. If 
a certain temperature is not 
essential the inlet pipe may be 
connected with the street main, or some other source 
of supply. An overflow pipe larger than the inlet 
must be provided, as shown. 

If brine, oil or some favorite mixture is used the 
liquid may be taken as it comes from the overflow 
and pumped to a tank located a few feet above the 
bath. A pipe from this tank 
allows the liquid to return to the 
bath by gravity. Where there 
is danger of the liquid becoming 
heated a bath of the design 
shown in Fig. 277 is used. The 
liquid is drawn from the bath by 
means of a pump and forced 
through coils of pipe in an outer tank and returned to 
the bath as shown. This form may have many modi- 
fications. The writer knows of one hardening plant 




Fig. 277. 



228 



FORGE-PRACTICE. 



located on the bank of a river where the cooling 
coils are run into the river at some distance below 
the surface. This is necessary as many large pieces 
are hardened in the bath every day. 

For an all around bath for many kinds of work the 
form shown in Fig. 278 is excellent. The general 
design may be planned to meet the needs of the 

individual shop. There 
are six or more pipes up 
the sides of the tank which 
are perforated in such a 
manner that the water or 
other fluid is projected 
toward the center. If it 
is desired it may be so 
arranged as to have the 
pipes swing toward the 
center when hardening 
small pieces. The center 
pipe is much shorter and 
open at the top to allow 
the liquid to flow toward 
the surface. This form of 
bath is invaluable for such 
work as drills, taps and 
other pieces having grooves or flutes, as the liquid is 
able to reach every part of the surface. The liquid 
projected through the holes in the upright pipes 
against the irregular surface prevents the steam, 
resulting from the contact of red hot metal and the 
fluid, from pocketing at any point. 

When hardening cylindrical-shaped pieces whose 




MISCELLANEOUS WORK. 229 

ends as well as circumference must be hard, this 
bath will be found most effective as a pipe may be 
added above the tank and a jet thrown downwards. 
This, together with the jet coming up from the bot- 
tom, insures the hardening of the walls of counter- 
sunk center holes in such pieces as lathe mandrels, 
etc. 

In many instances the hardening of the entire 
surface of the cylindrical pieces without having here 
and there soft spots is found to be a difficult matter. 
The use of this bath properly arranged will obviate 
this difficulty. 

When work is heated in hardening boxes and 
dumped into a bath ununiform results are many 
times obtained as the pieces go into the bath in a 
body and slow cooling of some pieces follow. A form 
of bath that obviates this difficulty is shown in Fig. 
279 where wires are arranged so as to separate the 
pieces and cause them to rotate as they descend. 
The depth of the bath should be such that the pieces 
will be cooled below a red before reaching the bot- 
tom, or an agitator may be provided to keep them in 
motion until cool. 

Fig. 2 80 represents a bath that is many tirries used 
with good results when hardening pieces of various 
forms. The work travels down the inclined shelves, 
rolling over and over until the bottom is reached. 

Ball-shaped pieces are difficult to harden in a 
bath of ordinary construction, but show uniform 
results when quenched in one of the designs shown 
in Fig. 281. The depth of the tank must conform to 
the size of the pieces, although a deep tank insures 



230 



FORGE-PRACTICE. 



good results on both large and small work. The 
false bottom (a) may be of wire netting of a size 
that will not allow the piece to pass through. The 
liquid must enter at the bottom with sufficient force 
to prevent the pieces resting on the netting which, 
being inclined, causes them to move toward the 

Overflow Pipe 



\0 



I 

L--i 




\ \ ^ •>y^**'^'!i'^J^^yf/J'A^^^'J'V^'^:^^'^^'^'/J''y 



Supply Pipe. 



Fig. 279. 



lower portions from which they drop into the per- 
forated tray. The tray being removable may be 
raised occasionally and the pieces taken away. 

At times it is necessary to harden pieces of a size 
that do not show good results when immersed in a 
body of water, and which may be hardened satis- 
factorily if one or more large streams of water are 



MISCELLANEOUS WORK. 



231 



projected against the portions desired hard. Take, 
for instance, the block shown in Fig. 282 which is 
about 10" in diameter and 6" long. The projecting 
ends must be hard while it is immaterial whether 
the balance of the block is hard or soft. Repeated 
efforts to harden in a body of water where large, 




Fig. 280. 



strong jets were projected against the ends resulted 
in failure as steam was generated in such quantities 
that the water could not act on the portions desired 
hard. Excellent results, however, were obtained 
when the pieces were suspended and heavy streams 
of water projected against the ends as shown in Fig. 
283. By the use of this device the steam readily 
escaped into the air and did not retard the cooling 



232 



FOEGE PRACTICE. 



action of the water. This method of cooling may 
be modified to meet various conditions. In con- 
nection with the streams against the ends, pipes 
may be provided so as to force water against all por- 
tions of the piece if desirable. 




Fig. 281. 



While we have given several designs of baths, some 
of which are intended for general use, and others for 
special kinds of work, it is many times necessary to 
make baths of a design that will accomplish a spe- 
cific result. It would not be possible to anticipate 
every requirement, and those in charge of heat- 



MISCELLANEOUS WORK. 



233 



treating departments must invent something that 
will insure the desired result. 




Fig. 282. 

While clear water is the medium most often used 
in baths, better results follow the use of other fluids 
at times, as for instance, brine which is a solution of 




Fig. 283. 



salt and water. The amount of salt varies accord- 
ing to the result to be attained, ranging from a small 
amount to enough to produce a saturated solution. 
Borax, alum, ammonia, cyanide of potassium, cor- 



234 FORGE-PRACTICE. 

rosive sublimate, citric acid, sulphuric acid and 
numerous other things are sometimes used. The 
use of cyanide and corrosive sublimate or any other 
violent poison is not advocated on account of the 
possibility of fatal results to those using them. 
While a solution of sulphuric acid and water many 
times insures a surface superior to that obtained by 
other mediums, its use is not advocated for articles 
that are not to be used and discarded within a short 
time, as it "rots" the steel. Dies and similar tools 
hardened in this bath, and laid away for a time, will 
be found worthless. It is claimed that steel hard- 
ened in this solution and then reheated to 650° F. 
will show no bad results, but, reheating to this 
temperature softens cutting tools so they are useless. 

For some classes of milling machine cutters and 
similar tools a bath of water having on its surface a 
thin layer of oil is valuable. The steel plunged 
through the oil has a thin coating of oil adhering to 
it, which retards the cooling action of the water to a 
certain degree, thus preventing the tendency to 
crack from too rapid contraction. 

Oil is much slower in action than water, and heated 
steel plunged into it has less tendency to warp or 
crack. Unfortunately, pieces made from carbon 
steel, unless quite small or thin, do not harden suf- 
ficiently for most purposes when quenched in it. 
However, articles of certain size and shape will 
harden nicely in it and when it will give the desired 
hardness its use is to be advocated. 

All oils are not alike in their ability to extract heat 
from steel, consequently different kinds are used 



MISCELLANEOUS WORK. 235 

to give a variety of results. Lard oil is used many 
times where toughness is desirable rather than 
hardness. Raw linseed oil, sperm oil, cotton-seed 
oil, fish oil and the various hardening and tempering 
oils are used either alone or mixed with one another, 
or with light mineral oils. 

At times borax, alum, soda, turpentine, beeswax 
and various other ingredients are placed in oil used 
in hardening. The use of turpentine, kerosene, or 
other ingredients having a low "flashing" point as 
an admixture is hardly to be advocated unless the 
party using it is thoroughly versed in its action, and 
is provided with equipment that makes their use 
safe. Serious burns, loss of life and property have 
resulted from some unwise attempts to follow some 
published statement of extraordinary results ob- 
tained. 

It is found possible at times to mix a heavy animal 
oil and a light mineral oil and produce good results 
in cases where neither one alone gave satisfaction. 

Water. — Water is used more than any other liquid 
as a medium for quenching red-hot steel in the 
process of hardening. Where but a small quantity 
is used in a still bath, it is undoubtedly true that best 
results follow the use of rain water, or of boiled water. 
Where it is necessary to provide a constant supply 
of fresh water it is customary to connect directly 
with a water main, or to pump from a stream or well. 
In such cases it is necessary to use the water without 
regard to its purity or its fitness for the work. One 
objection to such conditions is the varying tempera- 
ture of water from mains or rivers, and the extreme 



236 



FORGE-PRACTICE. 



coldness of that from wells, especially artesian wells. 
Water from the two former sources varies in tem- 
perature according to the seasons. 

As extremely cold water should seldom be used for 
pieces of intricate shape, and as, in most cases, it 

does not work as well as 
when at a temperature of 
70° F., it is advisable to 
provide some means of 
raising it to the desired 
temperature before it en- 
ters the bath. This may be 
accomplished by connect- 
ing a steam supply pipe 
with the inlet pipe, and by 
adjusting the flow of the 
steam by means of a valve 
so that the incoming water 
will be of the proper temp- 
erature. In a factory 
manufacturing tableware, 
such as spoons, forks, etc., 
it was found that the 
dies used in striking up 
this work showed a ten- 
dency to crack when quenched. It was found that 
the bath, which was quite ingenious in design, was 
supplied with water from an artesian well and was 
extremely cold. A steam pipe was connected with 
the supply pipe as shown in Fig. 284 and the water 
heated to from 60° to 70° F. before striking the heated 
dies, as a result the cracking was eliminated and the 



kiss) t^^ 


' 




'■ 


1, 




1 








1 




, 1 






I 




r^^fW 





Water 
Supply 



Fig. 2i 



MISCELLANEOUS WORK. 237 

dies were found to stand up as well or better than 
before. 

It will be seen that the quenching device in Fig. 284 
was made up of two pipes, the outer one somewhat 
larger than the inner. The inner pipe had holes 
drilled through its walls so that the water, under the 
pressure of the pump, would pass through and strike 
the die held in the inner pipe, which was made to 
act as a drainage pipe. The water was conducted 
away fast enough so that there was no body of water 
in the inner pipe. As the water was projected in 
numerous jets all vapor was carried away and 
could not pocket at any part of the die. A modi- 
fication of this form of bath could be successfully 
applied to many classes of work where steam causes 
soft spots by collecting at some essential portion 
when work is immersed in a body of water. 

It is undoubtedly true that a deep penetration 
can be obtained by the use of the design just con- 
sidered. Experienced hardeners know that jets of 
water properly applied are more effective, especially 
in the case of large pieces, than a body of water even 
when the latter is of generous proportions. 

Use of Salt. — There are pieces that do not show up 
favorably when quenched in brine because of its 
drastic action on the steel and yet when quenched 
in water do not seem to show a uniform surface hard- 
ness, occasioned probably, by a slight oxidation of 
the surface. This oxide not scaling off uniformly 
does not allow the water to attack the surface at all 
points as it should. In such cases a handful of fine 
table salt sprinkled on the surface of the bath at 



238 rORGE-PRACTICE. 

the moment the piece is immersed will work wonders, 
as it causes the oxide to scale off, thus leaving a clean 
surface for the water to act on. 

Many times where a brine bath does not work 
well a weaker solution of salt and water will be found 
to work satisfactorily. The amount of salt will 
depend on the character of the work. If the article 
to be hardened is made of high-carbon steel a weaker 
solution should be used than for one containing less 
carbon. 

Quenching with Steam, Vapor and Water Sprays. — 
There are conditions under which pieces will harden 
more uniformly and satisfactorily if quenched in the 
open by means of jets of steam, or vapor, or by sprays 
of water so arranged that all portions desired hard 
will be acted on by the quenching medium. 

The hardener in a plant doing job work encounters, 
occasionally, pieces that do not harden well when 
dipped in a bath. Sometimes the shape is such that 
in spite of any arrangement of supply pipes steam 
will pocket at some point and retard the action of the 
cooling medium. The same piece if cooled in the 
open air by means of properly arranged streams of 
steam, vapor, or water jets, will harden well as the 
steam can readily escape into the atmosphere. At 
times very light pieces are hardened by means of 
jets of air, or by a volume of air; the air, however, 
should not be under very great pressure as volume 
rather than velocity counts in cases of this kind. 
However, on account of the oxidizing action of air on 
hot steel its use is not to be advocated unless the work 
is done by one entirely familiar with the process. 



MISCELLANEOUS WORK. 239 

Hardening. — Steel is hardened by heating to a 
red and plunging in some cooling bath. The par- 
ticular cooling medium must depend on the size and 
shape of the piece, on the use to which it is to be put 
and also upon the composition of the steel from 
which it is made. 

The commonly used baths are water, brine, and 
water containing some substance such as borax, 
alum, etc., oil, tallow, or some of the so-called fats. 
This subject is more fully taken up under the subject 
of baths. 

The exact temperature to which steel must be 
heated to harden cannot be stated arbitrarily, as a 
tool having slender portions easily acted on by the 
bath need not be given as high a temperature as a 
large bulky piece, but in no case should it be heated 
hotter than is necessary to produce the desired re- 
sult, as temperatures that are higher than necessary 
perceptibly weaken steel. 

When one considers the enormous strain to which 
the cutting edge of a tool is subjected when in use it 
will be seen that the maximum of strength is essen- 
tial. 

The necessity of uniformly heating steel is more 
pronounced when hardening than with any of the 
other heat-treating processes. It is absolutely es- 
sential that no portion of the piece be overheated as 
this will produce an ununiform grain and the over- 
heated portion will be weakened even though it is 
allowed to cool to the temperature of the balance of 
the piece before quenching in the bath. 

When a die (Fig. 285) is heated too rapidly in the 



240 



FORGE-PRACTICE. 



fire the corners and edges are overheated. When the 
piece is quenched in the bath it cracks, or the over- 
heated portions break off as shown. If for any rea • 
son any portion of a tool becomes overheated, it 
should be removed from the fire and allowed to cool. 
It may then be reheated for hardening. 

While steel should never be overheated, there is 
less danger of permanently harming it from so doing, 
than if most of it was brought to the proper tem- 
perature and the balance overheated. It is safe to 
say that a large percentage of the troubles experi- 




FiG, 285. 



enced when hardening are due to the fact that the 
steel is not heated uniformly. 

It is essential that the cooling of a piece of steel in 
hardening should be as uniform as possible. During 
the cooling process contraction takes place; if the 
contraction is too ununiform the steel will be torn 
apart. If one portion cools rapidly and becomes 
hard and unyielding while the portion next to it 
continues contracting it is almost sure to crack. 

For this reason it is necessary many times to 
retard the cooling of some section, which may be 
done by covering the portion to be cooled slowly. 



MISCELLANEOUS WORK. 



241 



with a previously prepared piece of iron, or smearing 
it with oil or soap while red hot and just before it is 
quenched. Examples of this practice will be shown 
under "Hardening Dies." 

At times the inequality of contraction may be 
overcome by dipping a heavier section first, then 
gradually immersing the lighter portion as shown in 
Fig. 286 where an axe is being dipped in the bath. 




Fig. 286. 



It is a mistake to assume that extremely cold baths 
are always necessary, for while the degree of hard- 
ness depends on how quickly the heat is extracted, 
extremely cold baths do not always absorb heat from 
steel as rapidly as those that are not as cold, and 
the shock to the steel is not nearly as great if the 
chill is removed from the quenching fluid. 

For many classes of work, baths that are at a 
temperature of from 80° to 100° F. are found to give 



242 FORGE-PRACTICE, 

excellent results, while for thin pieces where extreme 
hardness is not essential and toughness is desirable, 
the contents of the bath may be considerably warmer 
than the temperature mentioned. 

Testing for Hardness. — The methods formerly 
employed in hardness tests consisted in trying the 
surface with a file, and the depth of penetration with 
a center punch, these in connection with the obser- 
vation of the fracture of an occasional piece made it 
possible for the skilled man to work within the former 
allowable limits. To-day the demands on the 
finished product make it necessary to use more 
reliable methods of testing. 

To be sure the Brinnel Ball Indenting Machine 
and several similar devices were used in an occa- 
sional laboratory, and excellent results were and 
are obtained by these systems when in the hands of 
expert mathematicians experienced in this particular 
line of work, but they are of little value in the 
ordinary plant. It is generally accepted that the 
perfect tool must have a hardness three times that of 
the metal it is to cut. To obtain this necessary 
hardness one must know that the proper tempera- 
ture cannot be exceeded when hardening, or excessive 
brittleness will result. To overcome this brittle- 
ness the temper must be drawn to a degree that 
makes the tool too soft to accomplish desired results. 
By means of the " scleroscope " it is possible to 
measure the degree of hardness, and also to ascer- 
tain whether the steel has been properly heated. 

Steel of a certain carbon content hardened at the 
proper temperature should show a certain sclero- 



MISCELLANEOUS WORK. 243 

scope reading. It is customary in some shops to 
take a test piece from a bar of steel from which a 
number of costly tools are to be made. The test 
piece is hardened under the very best of conditions 
by a skillful hardener and the degree of hardness 
found by means of the "scleroscope." A record is 
made of the reading, and when the tools are hard- 
ened it is used in determining whether they are in 
the best possible condition. 

The Shore Scleroscope consists of a small hammer 
whose striking point is a diamond of rare cleavage 
formation whose striking surface is slightly rounded. 
This hammer works in a vertical tube as shown in 
Fig. 287. Graduations which read from o to 140 are 
provided. The operation of the machine is so 
simple that it can be successfully used by anyone 
who has sufficient intelligence to enable him to work 
in a heat-treating room. The hammer is raised 
to the top of the instrument by pressing a bulb as 
shown in Fig. 288 where the instrument is being used 
in testing a projectile. When the hammer reaches 
the top of the tube it engages with a hook which 
holds it suspended. The leveling rod at the right of 
the scale Fig. 287 enables the operator to determine 
when the instrument is plumb, adjustment is 
effected by means of the knurled leveling screws. 
The hammer is released by again pressing the 
bulb and drops to the work. The rebound of 
the hammer indicates the degree of hardness of 
the piece. 

The surface that is to receive the blow must be 
perfectly smooth in order to insure correct readings. 



244 



FORGE-PRACTICE. 



Instructions accompany the instrument and should 
be followed as closely as possible. 

The hardness of i per cent carbon tool steel prop- 




PiG. 287. 

erly treated is about 100; 90 is a low value and no is 
considered high. 

As previously stated it is generally accepted that 
the perfect tool must have a hardness three times 



MISCELLANEOUS WORK. 



245 



that of the metal it is to cut. Unannealed tool steel 
of I per cent carbon content is found, by test, to 
have a hardness of from 40 to 45 points. According 
to the rule just quoted a tool could not be hardened 
so as to cut this satisfactorily; however, the same 
steel properly annealed shows a hardness of only 
30 to 31 points, and as a tool made from i per cent 
carbon steel properly 
hardened should show 
95 points, or better, it 
becomes an easy matter 
to produce satisfactory- 
results. From the ex- 
ample just cited it is 
apparent that the instru- 
ment can be used to de- 
termine whether steel is 
properly annealed. In 
this way thousands of 
dollars can be saved in 
cutting tools if the an- 
nealed product is tested 
before machining. 

High-speed steel when hardened does not show as 
high hardness test as good grades of carbon tool steel. 
The effectiveness of high-speed steel does not depend 
altogether on its hardness, but rather on the fact 
that it does not lose its ability to cut when heated 
to temperatures that would entirely soften carbon 
steels. 

The writer earnestly advises men engaged in the 
heat treatment of steel to make a study of the testing 




Fig. 288. 



246 FORGE-PRACTICE. 

of materials. Not only is it possible to accurately 
determine the quality of the annealed or hardened 
product, but it is also possible to determine whether 
steel has been overheated, or underheated, or un- 
uniformly heated, by the use of the instrument we 
have been considering. 

By finding the hardness of a metal to be machined, 
it is possible to determine the carbon content of a 
steel for use in making tools for machining it. The 
uses to which the instrument can be put are so 
numerous and varied that a volume could be written 
on this subject. 

Tempering. — Hardening steel sets up brittleness 
and strains. Tempering is resorted to to remove 
these. The temper of a piece should never be 
drawn any lower than is absolutely necessary as the 
operation softens the steel. The process of temper- 
ing is carried on by heating the hardened steel until 
the brittleness is reduced the right amount, and 
this is determined by the amount of heat it absorbs. 
This heating is done by various means. 

Color Method. — When tools and other articles are 
tempered by the color method, the amount of heat 
absorbed by the steel is determined by the colors 
on the surface due to a thin film of oxide which 
forms when the temperature reaches 420° F. and 
changes in color as the heat increases. In order to 
see these colors the surface of the hardened steel 
must be brightened by some means. Most hard- 
eners provide themselves with a buff-stick, which is 
a piece of wood with emery cloth attached. The 
steel is heated over a fire, or on an iron plate over a 



MISCELLANEOUS WORK!. 



247 



gas jet, or on a. piece of very hot metal, or by any 
convenient way. 

Temper Colors. — While the color method is not the 
most accurate, it provides a convenient way that 
answers very well where but a few pieces are to be 
done. When the heated piece reaches a tempera- 
ture of 430° F., a very pale yellow is visible on the 
polished surface. Every few degrees of heat causes 
changes in the colors as set forth in the accompanying 
table : 

Temper Colors 



Color. 

Very pale yellow 

Bright yellow 

Pale straw yellow 

Straw yellow 

Deep straw 

Dark straw 

Yellow with brown 

Brown 

Brown with red spots . . . . 
Brown with purple spots . 

Light purple 

Full purple 

Dark purple , 

Light blue 

Blue 

Dark blue 

Blue tinged with green . . . 



Degrees C. 



221 

227 
232 
238 
243 
249 

254 
260 
266 
271 
277 
282 
288 

293 
299 
316 
332 



Baths for Tempering. — A bath of oil provides a 
very satisfactory method of tempering where many 
pieces are to be heated or where the nature of the 
articles renders the use of the color method inad- 
visable. The pieces are placed in a perforated pail 
which is suspended in a kettle of oil placed over a 
fire, or in the regular oil tempering furnace as in 



248 



FORGE-PRACTICE. 



Fig. 289. The temperature of the oil is gauged by 
means of a thermometer. If the pieces are large, 
or have some sections heavier than others, the tem- 
perature of the oil should be raised gradually to insure 
uniform results. The oil should be agitated fre- 
quently, being careful that none is thrown outside 

of the kettle. The 
kettle should be pro- 
vided with a cover 
which has a long 
handle so that in case 
the oil catches fire the 
cover may be placed 
in position, thus smoth- 
ering the blaze which 
might endanger the 
operator and property. 
Oils with a high flash 
test may be used. 
Heavy black cylinder 
oil is supposed to have 
a flash test of 725° F. 
The manufacturers of 
some special temper- 
ing oils claim a flash 
test of 750° F. for their products but experience 
does not bear out these claims. In ordinary tem- 
pering it is seldom necessary to exceed 630° F. and 
these tempering oils are perfectly satisfactory up to 
and above this point. 

When an oil tempering furnace is not at hand and 
temperatures ranging from 430° to 560° F. are de- 




FlG. 289. 



MISCELLANEOUS WORK. 



249 



sired the following alloys may be used. This table 
was compiled by Mr. O. M. Becker and shows the 
melting points of the various alloys of lead and tin. 







Melting Tem- 






Melting Tern- 


Lead. 


Tin. 


perature. 
Degrees F. 


Lead. 


Tin. 


perature. 
Degrees F. 


14 


8 


420 


24 


8 


480 


15 


8 


430 


28 


8 


490 


16 


8 


440 


38 


8 


510 


17 


8 


450 


60 


8 


530 


l8i 


8 


460 


96 


8 


550 


20 


8 


470 


200 


8 


560 



These alloys should be carefully made and then run 
into small strips in a mold. When used, bars 
having the desired melting point should be placed in a 
melting pot heated by gas, if possible, as gas flames 
are more easily controlled to the melting point. 
The insertion of the tool causes the metal to cool and 
set around the steel. If the heating is carried on 
gradually the tool should be uniformly heated to the 
desired temperature when the alloy melts clear of 
the tool. While this gives excellent results when 
properly carried on, it is necessarily^ costly and leaves 
room for unsatisfactory results in any but a skilled 
workman's hands. 

For temperature above 700° F. a bath of molten 
lead is used with good results if the lead is agitated 
frequently. This is necessary as lead forms a ' ' dead' ' 
bath, that is, it does not circulate freely, and unless 
artificial circulation is resorted to, the pieces will 
not be heated uniformly throughout. The tempera- 
ture of the bath must be gauged with a pyrometer 
as shown in Fig. 275 and the pieces, especially if large, 



250 rORGE-PRACTICE. 

allowed to remain until they are heated to the tem- 
perature of the lead. 

The workman should always bear in mind the fact 
that steel hardened at the proper temperature is the 
strongest possible. If this temperature is exceeded, 
unnecessary brittleness results which necessitates 
drawing the temper lower than it should be, thus 
leaving the tool softer than is consistent with best 
results. A tool hardened at the proper tempera- 
ture by one man, and drawn to 400° F. gave splendid 
results. A similar tool made from the same bar, 
hardened by another man had to be drawn to 460° F. 
to prevent the cutting edge from flaking. The first 
tool did more than ten times the amount of work, 
and could be run considerably faster. 

There are several forms of tempering machines on 
the market. Some of these, especially those having 
revolving trays that hold the pieces of work, give 
very good results. Such a furnace is shown in Fig. 
290. It must be borne in mind, however, that the 
thermometer provided does not necessarily register 
the temperature of the steel, and, therefore, due 
allowance must be made for this difference. For 
this reason this machine may be run so as to give 
good results where a given size and kind of piece is 
being tempered right along, and it is for this condi- 
tion the machine is made. 

While red-hot plates are commonly used in tem- 
pering, and answer very well for small pieces whose 
shape is such that sudden expansion at some portion 
does no harm, there are many classes of work where 
their use is not to be advocated. If it is desirable 



MISCELLANEOUS WORK. 



251 




Fig. 290. 



252 



FORGE-PRACTICE. 



to use a plate the one shown in Fig. 291 answers the 
purpose very well. The end farthest away from 
the flame should be the starting point of the piece 
being tempered and it is gradually advanced toward 
the hot portion. By keeping the plate filled with 



Iron Plate 



"IP^P 




Fig. 291. 

pieces, and as some are pushed off into the oil and 
others placed on the cool end, a considerable amount 
of work may be done. 

Drawing in Sand. — A long-handled pan as shown in 
Fig. 292 provides a means of uniformly tempering a 
great many small pieces in a relatively short time. 




Fig. 292. 



Nothing but clean sand should be used. By holding 
the pan over an open fire and constantly moving it 
back and forth uniform results may be obtained. 
Articles having sharp edges and corners should not 
be drawn in a sand-shaking pan. 



MISCELLANEOUS WORK. 253 

Thermometer Scales. — While there are three ther- 
mometer scales in general use — namely the Fahren- 
heit (F.), Centigrade (C)., and Reaumur (R.) — but 
two of these enter into calculations in heat-treating 
plants in the United States. The Fahrenheit is used 
in English-speaking countries, and the Centigrade in 
several countries on the continent, and to a consid- 
erable degree in scientific work. As a great many of 
the writers on the subject under consideration state 
temperature readings according to the Centigrade 
scale and most men employed in heat-treating plants 
bave heen educated to think according to the Fahren- 
heit scale it seems wise to give the comparative table 
of Fahrenheit and Centigrade readings. 

The freezing point of fresh water is marked at 32 
degrees on the Fahrenheit scale, and at o on the 
Centigrade, while the boiling point, at atmospheric 
pressure is marked at 2 1 2 degrees on the Fahrenheit 
and at 100 degrees on the Centigrade. 

The table on p. 254 is obtained by use of the fol- 
lowing rule. 

To convert Fahrenheit into Centigrade Readings: 
Subtract 32 from Fahrenheit, divide remainder by 9, 
and multiply by 5. 

Example: Change 430° F. to C. 

432-32=398 398-7-9=44.22 44.22X5 = 221.1. 

Ans. 430° F = 22i.i°C. 
To convert Centigrade into Fahrenheit Readings: 
Divide by 5, multiply by 9 and add 32. 

Example: Change 788° C. to F. 
788-^5 = 157.6 157.6X9 = 1418 1418^32 = 1450 F. 

Ans. 788° C. = i45o°F. 



254 



FORGE-PRACTICE. 



Fahrenheit and Centigrade Thermometer Scales. 


F. 


c. 


F. 


c. ! 


F. 


c. 


-40 


-40 


190 


87.8 


1300 


704.0 


-35 


-37-2 


195 


90.6 


1350 


732.0 


-30 


-34-4 


200 


93-3 


1400 


760.0 


-25 


-31-7 


205 


96.1 


1425 


773-9 


— 20 


-28.9 


210 


98.9 


1450 


788.0 


-15 


-26.1 


212 


100. 


1475 


801.6 


— 10 


-23-3 


215 


lOI .7 


1500 


816.0 


- 5 


— 20.6 


225 


107.2 


1550 


844.0 





-17.8 


250 


121 .2 


1600 


872.0 


5 


-15 


300 


148.9 


1650 


899.0 


10 


— 12.2 


350 


176.7 


1700 


926.0 


15 


- 9-4 


400 


204.4 


1750 


954-0 


20 


- 6.7 


425 


218.3 


1800 


982.0 


25 


- 3-9 


430 


221 .1 


1850 


lOIO.O 


30 


— I I 


440 


226.7 


1900 


1038.0 


32 


0.0 


450 


232.2 


1950 


1065.5 


35 


17 


460 


237.8 


2000 


1093.0 


40 


4-4 


470 


243 -3 


2050 


II2I .0 


45 


7-2 


480 


248.9 


2100 


II49.O 


50 


10. 


490 


254 -9 


2150 


II76.5 


55 


12.8 


500 


260.0 


2200 


1204,0 


60 


15.6 


510 


265.6 


2250 


1232.0 


65 


18.3 


520 


271 .1 


2300 


1260 


70 


21 .1 


530 


276.7 


2350 


1287.5 


75 


23 -9 


540 


282.2 


2400 


I315.5 


80 


26.7 


550 


287.8 


2450 


1343 


85 


29.4 


560 


293 -3 


2500 


1371-0 


90 


32.2 


570 


298.9 


2550 


1399.0 


95 


350 


580 


304 -4 


2600 


1426.5 


100 


37-8 


590 


310.0 


2650 


1455.0 


105 


40.6 


600 


315 6 


2700 


1483 


no 


43-3 


610 


321. 1 


2750 


I5I0.0 


115 


46.1 


620 


326.7 


2800 


1537-5 


120 


48.9 


630 


332.2 


2850 


1565 


125 


51-7 


650 


343-3 


2900 


1593 


130 


54-4 


700 


371 I 


2950 


1621 .0 


135 


57-2 


750 


398.9 


3000 


1648.5 


140 


60.0 


800 


426.7 


3050 


1676.0 


145 


62.8 


850 


454-4 


3100 


1705.0 


150 


6s. 6 


900 


482.2 


3150 


1732.0 


155 


68.3 


950 


510.0 


3200 


1 760 . 


160 


71. 1 


1000 


537-8 


3300 


1815.6 


165 


73-9 


1050 


565 . 5 


3400 


1871.1 


170 


76.7 


1 100 


593-0 


3500 


1926.7 


175 


79-4 


II50 


621 .0 






180 


82.2 


1200 


648.5 






185 


85.0 


1250 


676.5 







MISCELLANEOUS WORK. 255 

Toughening. — While full annealing relieves strains 
in steel and gives the maximum toughness, it does 
not always give the necessary degree of stiffness. 
In order to produce the toughness and stiffness nec- 
essary many different treatments are resorted to. 
The exact treatment necessary to produce desired 
results depends on the composition of the steel and 
the strains it is to receive when in use. 

Large, heavy pieces are many times heated tc 
the refining heat and partially quenched in water, 
after which they are allowed to cool in the air. The 
internal heat returns to the surface and toughens 
the external portion. Smaller pieces are partially 
or wholly cooled in oil and then reheated to give the 
desired result. The amount of heat given w^hen 
reheating varies from 500° to 1000° F. 

In other cases the pieces are brought to the refin- 
ing temperature and thrown onto a floor of dry sand 
in a room where a definite temperature can be main- 
tained. Where this does not produce the necessary 
degree of stiffness a gentle stream of warm air may 
be blown across the pieces. Better results follow 
this method when the articles are placed on wire 
racks so that the air may have free access to all 
parts. 

Large forgings are heated red hot and allowed to 
cool by piling in heaps and cooled where no draft 
of air can strike them. It is obvious that such 
treatment will result in an unevenly cooled surface 
especially if the steel contains more than 0.40 per 
cent carbon, as the more exposed portions will cool 
more quickly than the others. However, if the 



256 FORGE-PRACTICE. 

results are commercially satisfactory, the method 
commends itself on account of the comparatively low 
cost. 

Where large pieces are toughened by quenching in 
oil, it is necessary, in order to get uniformly good 
results, to heat to a given pre-determined temperature, 
quench in oil for a given number of seconds, and 
then allow the pieces to cool in the air. To insure 
satisfactory results by this method temperatures, and 
exposure to the bath, must be determined by experi- 
ment, and followed absolutely. 

In all shop processes it must be borne in mind that 
methods commercially possible must be followed, 
provided they produce results that are commer- 
cially satisfactory. 

Hardening and Toughening. — In the case of the pipe 
wrench jaw shown in Fig. 293 , it is necessary to harden 
the portion (a). Fig. 294, containing the teeth, and 
to toughen the rib (b) . This is accomplished by care- 
fully heating to the proper temperature, which in the 
case of steel of 0.70 per cent carbon is about 1475° F., 
then quenching the teeth by holding under a stream 
of water as shown in Fig. 294. When the red has 
disappeared from the teeth the piece may be im- 
mersed in oil and allowed to remain until cold. 

A method of toughening practiced in some places 
consists in heating to a low red and burying in damp 
sand, after which they may be reheated to a tempera- 
ture that insures the desired strength and tough- 
ness. While this method gives satisfactory results 
on certain kinds of work, it is doubtful if it produces 
as great a degree of strength and toughness as 



MISCELLANEOUS WORK. 



257 



though they were quenched in oil and then tem- 
pered. 

Articles that have heavy and light sections ad- 
joining each other and where both must be hardened 
require special care when quenched or the unequal 
contraction, incident to the difference in size, may 





Fig. 293. 



Fig. 294. 



result in cracks or breakage. The T slot cutter 
shown in Fig. 295 is an example that answers well as 
an illustration. It is necessary to harden, not only 
the cutting portion, but also the neck (6) in order to 
give it the necessary stiffness and to prevent its 
roughing up when in use. 



258 



FORGE-PRACTICE. 



To prevent the tool cracking when quenched it is 
advisable to wind soft iron around the neck at a and 
close up to the body. If small wire is used it is 
necessary to pass the wire several times around the 
piece. As the wire is red hot at the time of quenching 
sudden contraction at this point is avoided. 

At times tools of this kind have extremely large 
center holes in the end that is to be hardened. Such 
holes should be filled with fire clay dough before the 
pieces are placed in the fire. This precaution should 




Fig. 295. 



always be observed except in the case of tools that 
are to run on centers. 

The Magnet in Hardening. — When steel is heated it 
retains its ability to attract the magnetic needle, or 
a magnet, to what is known as the decalescence 
point. When a piece of steel is heated in a fire that 
is hotter than the temperature to which the steel 
should be brought the metal absorbs heat fairly 
constantly until a certain temperature is reached, 
when there appears to be a lag in the process; this 
is known as the decalescence point. At this tempera- 
ture the steel will neither be affected by the magnet, 
nor will it attract the compass needle. Care should 



MISCELLANEOUS WORK. 259 

be exercised that the tongs, or other holder ordinarily 
used is not present when the test is made, or the 
operator may be deceived. This same piece of steel if 
heated to a high temperature and allowed to cool, 
will, when at a certain temperature, show a lag and 
will, apparently, grow hotter even when cooling in 
the air. This is known as the recalescence point. This 
phenomenon takes place at a temperature ranging 
from 85° to 215° F. lower than the decalescence 
point. Steel must be heated to the decalescence 
point in order to harden, and it must be quenched 
before it drops to the recalescence point or it will 
not harden. Steel should be hardened at the highest 
temperature to which it should be heated, and on a 
rising heat, never on a descending heat. 

The use of the magnet is to be advocated, as the 
eye is not always to be relied upon. A man's bodily 
condition has a great deal to do with his ability to 
discern heats, and the lighting conditions many times 
cause one to be deceived even when the eye, under 
proper conditions, would give accurate results. As a 
man grows older, his eyes change and unless he has 
some standard to check up by he fails to discern 
heats, and is rated as a "back number" at a time 
when his long experience should make him invaluable. 
The trouble arises from the fact that the man will 
not acknowledge to himself that his eyes are changing 
and instead of realizing this and frequently checking 
up by means of a magnet, in the absence of a pyrom- 
eter, he goes on until it is apparent to everyone that 
his days of usefulness are past. And many times 
this is due to the fact that he did not ' ' check ' ' him- 



26o FORGE-PRACTICE. 

self frequently rather than to admit a change of eye- 
sight, or ability. 

A very successful hardener who is working in a 
factory where every appliance for producing good 
results is employed "checks up" ten to fifteen times 
a day with a magnet. He says he is not sure of his 
heats when he returns to his fire after leaving and 
going where the light conditions are different. Most 
workmen are not aware of the harmful effects of a 
slight variation in temperature on certain classes of 
tools. The fact that a tool hardened without 
cracking or undue distortion is no proof that it is in 
the best possible condition for the use it is intended 
for. 

While the decalescence point is not in all cases 
the most suitable temperature to be employed in 
hardening, it is a safe guide as to the lowest point at 
which the steel will harden properly. The exact 
amount of additional heat necessary to produce some 
desired result necessitates a knowledge gained by 
experience, but the inexperienced man can gain this 
knowledge by diligent study and intelligently con- 
ducted experiments. 

Springing. — Springing many times results when 
pieces are hardened. This may or may not be the 
hardener's fault. The careful man will use every 
precaution possible to prevent distortion, but the 
cause of the trouble may not be anything that he has 
done, or anything he could counteract had he known 
of it before hardening. As previously stated the 
piece of steel may have been straightened cold, or 
the piece may have been machined with a dull cut- 



MISCELLANEOUS WORK. 261 

ting tool which set up strains in the steel. The 
opening of a blanking die may have been worked out 
a trifle too large and then pened in cold in which 
case distortion might result when the die was hard- 
ened. Long, slender pieces should never be placed 
in a furnace, in such a manner that they could bend 
from the weight of the metal when red hot. If pos- 
sible, heat in a furnace of the design shown in Fig. 26S ; 
if this is not possible place in a tube and turn fre- 
quently. When it has reached the proper hardening 
temperature remove the tube from the furnace and 
stand in an upright position before taking the piece 
from the tube. As the piece is lifted vertically the 
tendency to spring is much less than if it was 
heated in a horizontal position on the floor of the 
furnace, drawn out and then brought to a vertical 
position preparatory to dipping in the bath. 

Pieces of this kind should be lowered into the bath 
in as nearly a perfectly vertical position as possible 
to prevent one side cooling faster than the other. 
Pieces of the description under consideration give 
best results when pack hardened and quenched in 
oil. However, if the ordinary fire and water method 
must be used, have the contents of the bath at a 
temperature of from 80° to 90° F. 

Straightening. — If extreme care in heating and 
quenching is exercised, springing or other distortion 
will be reduced to the minimum. However, pieces 
will some times go out of true and must be straight- 
ened, by first heating the articles and then applying 
pressure. This pressure should be gradual and 
should be kept up until the piece is cooled. If the 



262 FORGE-PRACTICE. 

article is not too large in cross-section and has centers 
in its ends it may be placed between the centers of a 
lathe, then heated by means of a Bunsen burner, gas 
jet, or spirit lamp, until lard oil applied to the sur- 
face commences to smoke, after which pressure may 
be applied to the convex side by means of a tool 
shank held in the tool post. The pressure should be 
sufficient to spring the article slightly in the opposite 
direction, when it may be cooled by applying wet 
cloths or waste uniformly to all parts of the surface; 
or it may be left between the centers until cooled by 
the air. If it is found to be sprung when tested it 
should be reheated and the above operation repeated. 
Do not attempt to spring hardened steel without 
heating, no matter how many times it has pre- 
viously been heated. Hardened steel cannot be 
bent when cold by a man of ordinary experience with 
any degree of safety. Slender pieces are sometimes 
straightened after the temper is drawn, and when 
cold, by pening, by men experienced in this work, 
but this practice is not to be advocated. 

Pieces that have no centers can be straightened 
in a screw press. It is necessary to support them on 
blocks located a convenient distance apart, and 
applying pressure between them after heating. 

Changes in Length. — Steel of ordinary composition 
has a tendency to change in length when hardened. 
This can be overcome, to a degree, by annealing at a 
temperature somewhat higher than hardening heats 
after the pieces are rough machined. Steel contain- 
ing certain elements has less tendency to change than 
others and for this reason is advocated for use in mak- 



MISCELLANEOUS WORK. 263 

ing taps. Taps that are annealed as described above 
and then pack hardened have Httle tendency to a 
change of pitch. Consequently this method is ad- 
vocated whenever possible for this class of tool, 
particularly where change of pitch is fatal to the tool. 

Value of Experiments. — It is advisable, at times, to 
vary the treatment given a tool and then closely 
watch results when it is set to work. This does not 
apply where satisfactory results are being obtained 
by some method that has been found to work all 
right; but, in the case of a new kind of tool; or, 
where a tool is being used on stock entirely different 
from that used before. 

The character of the work a tool is to perform, 
and the composition of the steel from which it is 
made must be known in order that the right treat- 
ment may be given it. No experienced hardener, 
or technical expert, for that matter, can always tell 
offhand the best treatment to give a tool unless the 
conditions mentioned are known. He can in all 
probability give a safe course to pursue in treating it, 
but this should not be the prime essential to be con- 
sidered, regardless of the capability of the tool to do 
the maximum amount of work in a given time. It 
is, of course, necessary to keep an accurate account 
of the cost of the various operations performed in a 
heat-treating department, the same as in any other 
part of the factory, but because a certain operation 
cost a given sum to pf^rform at some previous time is 
no reason that a treatment costing several times as 
much is not advisable if results in the use of the tool 
warrant the added expense. 



264 FORGE-PRACTICE. 

If the material from which the tool is made plus 
the cost in the tool room of getting it ready for the 
hardener aggregates $50 it is poor policy to pursue 
a method in hardening that costs but 50 cents, 
when a method that involves an expense of !i^5 would 
put the tool in condition to produce many times more 
work before it was scrapped. Yet this "penny wise, 
pound foolish" system is still adhered to in some 
shops. The expense account should rather be kept 
with the tool; its cost of production and mainte- 
nance, as against the amount of work produced by it, 
etc. 

The entrance of technically educated men into 
factories has done a great deal toward eliminating 
many of the foolish practices in some plants. The 
technically educated man, however, should "serve 
his term" in the heat-treating room and the pro- 
duction departments getting familiar with operations 
and requirements before he is permanently located in 
the c?iemical laboratory and allowed to dictate the 
course and methods to be pursued in the heat- 
treating department, as otherwise a condition less 
desirable than that occasioned by "hit or miss" 
methods may, and probably will, result. 

So far as possible each class of tool that is heat 
treated should receive personal consideration. Its 
chemical analysis, design, material it is to cut, 
amount of work it is to produce in a given time, and 
conditions under which it is to work should be taken 
into account in determining the treatment it should 
receive. At times a slight variation in temperature 
or time exposure will work wonders. A certain class 



MISCELLANEOUS WORK. 265 

of tool that had been hardened from a temperature 
of 1400° F. was heated to 1430° F. and an increase 
of 50 per cent in the amount of work produced by 
the tool was obtained. A tool made from a well- 
known alloy steel was hardened at 1375° F. accord- 
ing to instructions on the bar, with fair results. On 
the advice of a representative of the concern from 
whom the steel was purchased, one of the tools was 
hardened at 1500° F. and results way beyond any- 
thing thought of were obtained. The writer does not 
wish to be understood as advocating high tempera- 
tures when heating steel for any of the heat-treating 
processes, but in the case just cited the heat men- 
tioned was needed to bring out certain qualities in 
the steel. 

At times a trifling drop in temperature will work 
wonders especially in the case of cutting tools having 
projecting cutting teeth. In some cases a micro- 
scopical examination of the surfaces of the fracture in 
the body of the tool might show that the steel was 
underheated, while a similar examination of a 
broken tooth would indicate correct heating and yet 
both body and teeth might have been at the same 
temperature so far as is humanly possible to heat 
such pieces. In the case just considered the cutting 
teeth are the portions to be considered, consequently 
the temperature employed must be one that gives 
best results here. This case emphasizes the repeated 
statements of writers dealing with the subject under 
consideration that variations of temperature are 
necessary for pieces of different sizes and shapes 
made from steel of the same composition. 



266 FORGE-PRACTICE. 

Annealing. — The term annealing, as generally 
understood, means the softening of materials so that 
they will be workable. At the present time, and by 
those engaged in the heat treating of steel, the word 
has a much broader meaning. Crucible tool steel as 
it leaves the finish hammer, or rolls in the steel mill is 
quite hard and filled with strains. The condition of 
hardness renders machining difficult, or impossible. 
To overcome this difficulty, and to remove the strains, 
the steel is heated to a uniform red and allowed to 
cool slowly. 

The exact temperature to which a piece of steel 
should be heated for annealing depends on the crit- 
ical temperature of the steel. This temperature 
varies somewhat and depends on the composition of 
the steel, on the size, and on the subsequent treat- 
ment it is to receive. However, it is generally 
advisable to bring -the steel to a somewhat higher 
heat than it is to receive when hardened. In this 
way it is reasonably certain that strains that would 
otherwise be relieved by the hardening heat, will 
be eliminated in the annealing. The exact increase 
in temperature above the critical point cannot be 
"stated arbitrarily, but in ordinary practice is about 
50° F. Where special objects are to be attained, 
this temperature is sometimes exceeded. However, 
very high annealing heats are liable to produce a 
product that is difficult to machine, for while it may 
appear to be soft under a file test, tools will dull 
rapidly when cutting it. 

Where it is necessary to heat pieces much more 
than 50° F. above the refining heat, in order to 



MISCELLANEOUS WORK. 267 

release strains that may manifest themselves when 
hardening, and where the pieces are to be machined, 
it is, at times, advisable to resort to ' ' double anneal- 
ing." That is, first, heat to the higher temperature 
and allow them to cool, then heat to a few degrees 
above the refining heat and allow them to cool the 
second time, thus doing away with the crystalline 
grain incident to the high heat. 

In any of the operations involved in the heat 
treatment of steel it is always advisable to heat as 
rapidly as possible and yet heat uniformly. On the 
other hand steel should not be heated too rapidly 
as ununiform heats may set up strains that are more 
serious than those we are attempting to remove by 
the annealing process. If a large die block, rect- 
angular in shape, is placed in the furnace and heated 
there is a tendency, unless care is exercised, to over- 
heat the corners and edges before the center of the 
block has reached the proper temperature. 

A piece of steel always shows the effect of the last 
heat it receives, and each portion of every piece 
shows the effect of the heat it receives, as a result, 
an overheated piece, if it is ununiformly overheated, 
shows an ununiform granular condition that varies 
throughout accordingly as the piece was heated. 
This granular condition indicates that the steel has 
been weakened, and if the weakening is not uniform 
throughout the piece it is in poor condition to be 
hardened, or to receive excessive strains of any kind. 
It is a mistake to keep a piece of carbon tool-steel 
red hot any longer than is necessary after it is uni- 
formly heated throughout, as prolonged heats, when 



268 FORGE-PRACTICE. 

annealing, even when the steel is not overheated, 
tends to weaken it, and to produce a condition that 
renders machining with cutting tools difficult. 

A mistake often made in annealing is to heat the 
piece too hot and to hold it at this heat for too long a 
time ; then when an attempt is made to machine it, 
difficulty is experienced. The piece is returned to 
the heat-treating department and it is heated hotter 
and kept hot longer than before, with the result that 
each time it is treated conditions are found worse. 

The writer recalls a die block, on the face of which 
an impression was to be made by engraving. After 
repeated attempts to anneal the steel, the block was 
sent to our plant. An examination of the grain of a 
piece cut from the block showed it to be extremely 
granular. While the steel showed soft under file 
test, it appeared to be extremely weak when broken, 
indicating excessive and long-continued heats. The 
block was placed in the furnace and carefully heated 
to the proper temperature, making sure that the 
temperature was uniform throughout. It was then 
removed from the furnace and buried in ashes. The 
ashes that came in contact with the steel were heated 
to a temperature of about 1000° F. while the balance 
of the ashes were not heated, but were perfectly dry. 
When the piece was cool it was found to be in excel- 
lent condition for machining. 

A method of annealing, where but a few compara- 
tively small pieces are to be treated, consists in 
heating to a red and burying in ashes, lime or asbes- 
tos and allowing them to remain until cool. If the 
pieces are properly heated, and the material they are 



MISCELLANEOUS WORK. 269 

buried in is warm and dry good results generally 
follow. Burying red-hot steel in cold or damp ma- 
terials has a tendency to partially harden it. A 
method practiced by some consists in heating a piece 
of scrap iron or steel to a red and burying in ashes, 
lime or whatever is used and allowing it to remain 
there until the piece to be annealed is properly heated, 
when it is removed and the steel buried in the heated 
material. 

Box Annealing. — Undoubtedly hundreds of thou- 
sands of dollars worth of steel is rendered unfit for 
use each year by this method of annealing; but, it is 
not wise to condemn a method because it is not 
properly done. 

As previously stated, the one who is responsible 
for the heat treatment of steel should understand 
steel. If a batch of small forgings made from a 
comparatively low carbon steel is to be annealed, 
it might be perfectly proper to use a method that 
might prove very unsatisfactory if the same pieces 
were made from medium or high carbon stock. 

It is poor practice to anneal a large box of small 
pieces made from high carbon steel, as the pieces 
located in various parts of the box would remain red 
hot for different lengths of time. As a result the 
action of the process would tend to produce a product 
that was not uniform and difficulty would be experi- 
enced when they were machined. 

Small pieces should be packed in small boxes, and 
the boxes removed from the furnace as soon as the 
contents are uniformly heated to the proper tem- 
perature. It is not to be understood that small 



270 



FORGE-PRACTICE. 



pieces made from low carbon steel would be so easily 
injured if packed in large boxes, as the lower the 
carbon the less sensitive the steel is to the injurious 
effects of long heats. Trouble is experienced here at 
times when the workman is told. "These pieces 
are made from machine steel," as the so-called ma- 
chine steel may contain a high percentage of carbon, 
and the effect of long-continued heats is just as 
apparent as though the stock was crucible tool steel 
of the same carbon content. 




Pig. 296. 

It is a good plan to use test wires as shown in 
Fig. 296 in order to determine when the pieces at the 
center of the box are heated to the desired tempera- 
ture. Several j" holes are drilled through the box 
covers as shown, and ye" wires are thrust down 
through the packing material to the bottom of the 
box. When the work has been exposed to the action 
of the heat for a time one of the wires may be drawn 
by means of long tongs and its condition noted. In 
a short time a second wire may be removed and this 
continued until one is drawn that shows the proper 
color. 



MISCELLANEOUS WORK. 27I 

The pieces should be arranged in the box so that 
they will not be within an inch of the walls at any 
point. The packing material used may be pul- 
verized charcoal, coal dust, lime, asbestos, sand 
or any material that will answer the purpose and yet 
have no undesirable effect on the steel. 

Some writers claim that a furnace heated to a 
given temperature will heat a piece of a given size 
and shape to a definite temperature in a given time. 
The writer's experience does not coincide with this 
claim. There are a number of conditions that have 
a decided effect on the exact length of time it takes 
steel to absorb heat. This is especially true of work 
packed in boxes. It is wise to have records showing 
the approximate time required to heat given 
sized pieces and boxes to certain temperatures, 
but such records should not be considered as 
absolute. 

It sometimes happens that an entirely unlooked- 
for and undesired result is obtained by packing the 
steel for annealing in material not suited for the pur- 
pose. Where low carbon steel pieces are to be 
annealed, and it is not desirable to increase the car- 
bon content, a packing material that will not impart 
carbon should be used. A batch of forgings were 
made for a manufacturer of guns which were to be 
machined and then bent to an irregular form. As it 
was necessary to anneal them to put them in con- 
dition for machining they were packed in boxes and 
no thought given to the action of the packing ma- 
terial. The material used was wood charcoal. 
When machined they cut nicely, but when an 



272 rORGE-PRACTICE. 

attempt was made to bend them to a finished form, 
they broke. Investigation showed that carbon was 
charged into them in the anneaHng process. In 
order to save the pieces and make bending possible 
they were re-annealed in forge scale (oxide of iron), 
which contains no carbon, and which absorbed the 
excess carbon from the forgings making cold bending 
possible. 

At times high-carbon steel pieces are packed in 
some material that draws the carbon out and leaves 
the steel unfit for use. This may be rectified by re- 
annealing in charred leather or charcoal, making 
sure that the time exposure for recharging is about 
the same as when the carbon was extracted. 

If it is desirable to use a high carbon steel and 
none is at hand the finished tool may be packed in 
charred leather and run at a temperature of 1400° to 
1450° F. from two to four hours, after which it may 
be allowed to cool and then hardened. 

The operator should understand that while certain 
materials are very desirable as packing materials 
when annealing certain pieces their use is to be dis- 
couraged for other purposes. Tool steel to be used 
for most cutting tools can be satisfactorily annealed 
if packed in charcoal; yet tools to be subjected to 
certain strains where an increase of carbon is unde- 
sirable should not be exposed to charcoal, or any 
other carburizer. They should not be heated in 
contact with decarburizers or the carbon content 
at the surface will be lowered. When in doubt as 
to the desirable material to be used it is best to 
select a neutral. The writer has in such cases used. 



MISCELLANEOUS WORK. 273 

with good results, finely sifted coal ashes, or dry fire 
clay. 

When one understands the action of different 
packing materials it is possible many times to treat 
a stock not exactly suited to a certain purpose in 
such a manner as to add to it, or take from it carbon, 
and accomplish the desired result. 

Articles made from sheet steel, or which are light 
in cross-section, if made from medium or high- 
carbon steel seldom show good results if box an- 
nealed. Take, for instance, jack-knife blades, 
springs, etc. Such pieces, especially if they are to 
be machined, are best annealed by heating in a fur- 
nace where no direct flame can strike them, removing 
as soon as uniformly heated to the proper tempera- 
ture and placing in a box, in the bottom of which is a 
quantity of hot ashes. As these pieces are con- 
stantly added they cool very slowly. When the 
box is nearly full the balance of space may be filled 
with hot ashes. The blades do not remain red hot 
very long, but cool very slowly from about 1000° F. 
The same pieces if box annealed would have a coarse 
structure and would give considerable trouble when 
drilled, or machined by any method. 

Water Annealing.— The opinions of writers and 
hardeners differ widely as to the value of water 
annealing. The opinion, as generally given, is that 
it is a good practice to let alone. There are times 
when it is necessary to anneal a piece of steel as 
quickly as possible, and if the shape of the piece is 
such that uniform cooling down to the point where the 
red disappears from the steel when the piece is held 



274 FORGE-PRACTICE. 

in a dark place is possible, fairly good results follow 
if it is immediately plunged in water, oil, or soapy 
water. 

There are times when it does not seem possible 
to anneal steel by the regular methods so that it will 
be in the desired condition, and where water annealing 
(so-called) will give satisfaction. The writer recalls 
some tap blanks that could not be threaded in the 
lathe without "tearing," that is, the stock would tear 
out on the sides of the thread. The steel appeared 
to be weakened by the annealing as there was not 
sufficient strength to hold it together under the action 
of cutting with the threading tool. As a last resort 
water annealing was tried. The blanks were heated 
to a low red and allowed to cool until they reached a 
point where fine dry sawdust would not sparkle 
when dropped on them, and then plunged in warm 
soapy water. After being treated in this manner 
there was no tearing of the stock and results were 
perfectly satisfactory. The writer does not wish 
to be understood as advocating this method of 
annealing. On the contrary he discourages its use 
only in exceptional cases, but there are cases where, if 
carefully carried on, very good results may be ob- 
tained. The cooling, however, must be uniform 
and this is difficult to accomplish unless extreme care 
is exercised as the lighter sections and edges have a 
tendency to cool more rapidly than the balance of 
the piece. 

In one shop where it is practiced on rather a large 
scale pieces of cast iron having a hole somewhat 
larger than the piece to be annealed drilled in from 



MISCELLANEOUS WORK. 275 

one end one inch deeper than the length of the piece. 
These are heated red hot, the red-hot piece of steel 
inserted in the hole, the end covered and the whole 
allowed to cool until the steel is to the desired 
temperature, when it is removed from the case and 
quenched in warm oil. 

Examples of Hardening. — As different kinds and 
forms of tools require different treatment, it seems 
advisable to consider them separately rather than to 
attempt to give general instructions. The one 
doing the hardening should consider each tool, or 
each batch of tools, to be treated as a problem, the 
solution of which depends on several conditions, 
namely, the use to which it is to be put; the steel 
from which it is made; the size and shape, and the 
treatment the steel has received before it comes to the 
heat-treating room to be hardened,. 

Let us first consider a piercing punch to be used 
in connection with a punch-press die as shown in 
Fig. 297. In order to determine the temperature to 
which it should be heated, a knowledge of the kind of 
steel used is necessary. If the carbon is compara- 
tively low, say 0.9 to i per cent, it will require a 
higher heat than if made from steel containing 1.25 
to 1.4 per cent. For the former, a temperature of 
1450° F. will be required, while for the latter only 
1425° F. should be given. The size of the punch is a 
determining factor also, as one |" diameter will not 
require as high a heat as one 2" diameter. An ab- 
solutely uniform heat is essential. Fig. 298 shows 
one of these punches that was not uniformly heated, 
,and when hardened, it was in the condition shown. 



276 



FORGE-PRACTICE. 



Some of these punches broke in the bath while others 
broke in use, all showing the same general appearance. 
When it was suggested that they had not been uni- 
formly heated, the claim was made that this could 
not be so, as the most modern appliances were used, 
a certain temperature was maintained in the fur- 
nace, and the pieces left in the furnace a certain 





Fig, 297. 



Fig. 298. 



length of time, the length of time having been 
determined by experiment. 

A punch from the same lot was carefully heated in 
a charcoal fire in a blacksmith's forge and quenched 
in the same bath used for the others, and did not 
show any weakness when tested or when put to use. 
Further investigation showed that the pieces had 
not been uniformly heated. As a result, the hard- 
ener was given orders to carefully observe the heat 
given each piece before quenching. 

Cold Chisels. — The efficiency of a cold chisel de- 
pends, in a large measure, on the treatment it 



MISCELLANEOUS WORK. 277 

receives when being forged. A piece of steel if im- 
properly treated in the process of forging cannot be 
hardened and tempered so it will do the amount of 
work it should. 

As a rule, a chisel to be used for ordinary work is 
made from steel containing 0.9 to i.i per cent car- 
bon. For many small chisels to be used for such 
work as die sinking, when light cuts are to be taken, 
and where the ability to hold a keen edge is essential, 
steel containing a higher percentage is used. The 
higher the carbon content the greater care necessary 
when forging. 

Small chisels should never be quenched in an ex- 
tremely cold bath, as this causes brittleness, and 
extreme toughness is the quality needed. For 
chisels of ordinary size (i") a bath whose tempera- 
ture is about 70° F. gives good results. As 70° F. is 
about the temperature of the ordinary room there is 
little need of gauging the heat. In extremely warm 
weather it may be necessary to add cool water occa- 
sionally. Very small chisels many times give excel- 
lent results, especially if the carbon content of the 
steel is high, if the bath is slightly warmer than that 
mentioned. 

The chisel should be uniformly heated to the de- 
sired temperature for an inch or more above the 
point to which the hardness is to extend. It should 
be worked up and down in the bath to prevent a 
"water line," and around, to avoid steam. When 
it is properly hardened, remove from the bath and 
brighten one side with the buff stick and draw the 
temper. 



278 FORGE-PRACTICE o 

Many hardeners draw the temper of medium size 
and large chisels by means of the heat left in the body 
of the steel after the cutting end is hardened, help- 
ing this out when necessary by holding it in the 
flame of the fire. Others contend that better re- 
sults follow when the piece is entirely cooled and 
then reheated for drawing. Either practice is good 
^ if carefully carried on. As the cutting end 

C^] of a chisel is thinner than the portion 
immediately back of it, extreme care must 
be observed when heating for hardening 
\ / or an uneven heat will result, and a break 
as shown in Fig. 299 will appear when 
quenching, or when the tool is used. 

As repeatedly stated, steel shows the 
effects of the last heat it receives, and as 
high heats perceptibly weaken it extreme 
care should be taken when hardening 
chisels. Do not heat any hotter than is 
necessary to refine the steel. Many times 
cold chisels receive less attention than 

\ 7 tools that cost more in making, but if one 

Fig. 299. will consider that a chisel properly forged, 
hardened and tempered will do many times 
more work in a day than one improperly treated, it 
will be seen that the same care should be exercised 
as when hardening a more costly tool. 

In many shops an account is kept of the amount of 
work done with a tool; original cost and upkeep 
placed in one column and the amount of work ac- 
complished with it, in the other column, thus making 
it possible to find the tool cost per piece of work. 



MISCELLANEOUS WORK. 279 

This practice in the case of a cold chisel may not be 
feasible, but the same care should be exercised in its 
treatment as would be in the case of a costly die or 
milling machine cutter with which an account was 
kept. 

Tempering. — Any tool hardened at the proper 
temperature will stand up in use with less "drawing 
back" than if given more heat. It is necessary at 
times to draw the temper of a chisel much more than 
it should be to give it the necessary toughness, be- 
cause it was overheated in hardening. If the tool 
is heated 150° above the refining heat, it will be 
necessary to draw the temper considerably more 
than it should be, thus we get extreme brittleness 
from the overheating, and softness from the tem- 
pering. 

It is not possible to give the exact temperature to 
which a chisel should be drawn, as the use to which 
it is to be put must in a great measure determine this. 
Small chisels used in die sinking and similar work 
are many times drawn to a full straw color (460° F.), 
while those used for rough, heavy work are drawn to a 
purple. The writer's experience has convinced him 
that for ordinary work, chisels of the average size 
give good results if drawn to a very deep brown with 
the red and purple spots just showing, then check in 
warm oil. Many hardeners check a chisel, after 
drawing, in cold water, which tends to set up a cer- 
tain amount of brittleness that is not apparent if oil 
is used. 

Punch-press Dies. — There are many kinds and pat- 
terns of dies used in punch-press work. We will 



28o FORGE-PRACTICE. 

consider first a few patterns of blanking dies. Prob- 
ably no one class of tools gives the hardener in a job 
shop more concern than blanking dies. If the size 
and design are, such that hardening is a simple task, 
the work is done in the shop where it is made ; on the 
other hand, if the die is liable to go to pieces as a 
result of heat treatment, it is sent to a place where a 
specialty is made of such work. There are many 
things to consider when hardening a die. First, the 
steel from which it is made; second, the treatment it 
has received in forging or annealing; third, the 
treatment it has received by the die maker, and 
fourth, the use to which it is to be put. 

Of course it is necessary that the hardener know 
whether the steel is low or high carbon, or some alloy 
steel (as oil hardening steel) that requires special 
treatment. The treatment it may have received in 
forging, annealing or by the die maker is difficult to 
find out and many times has to be ignored. If the 
die is to be used in punching hard or heavy stock, it 
ma3^ require different temper drawing than if it is 
to work on soft or thin material. 

If we are uncertain as to the forging or annealing 
it is a good plan to heat the die to a red, slightly 
above the hardening heat, remove it from the fire 
and allow it to cool. This is done to remove any 
strains. It may then be reheated to the desired 
temperature and immersed in the bath. When 
placing in the bath grasp it by means of tongs in 
such a manner as not to cover any essential part, and 
lower it endwise as shown in Fig. 300, swinging it back 
and forth so as to force the liquid through the open- 



MISCELLANEOUS WORK. 



281 



ings. A still bath of brine of generous proportions 
works nicely. While a bath of the description shown 
in Fig. 301 with a jet coming in from the side is often 
used for this purpose, better results follow the use of 
a still bath, as uneven cooling may result in warping 
the die. 




Fig. 300. 



When the die has cooled to the temperature of the 
bath, remove and hold over a fire and heat until 
moisture applied with the finger will steam from the 
heat in the steel. When doing this, turn the die 
repeatedly so that it will absorb the heat uniformly, 
which is done to remove hardening strains. The 



282 



FORGE-PRACTICE. 



surface may now be brightened and the temper 
drawn. 

Dies to be used in blanking pieces from soft steel 
may be drawn to a full straw color. 

In Fig. 302 is shown a die made from thin stock. 

j As this is used in punching cold rolled strip stock 

of 0.80 per cent carbon it is necessary to use extreme 

care in heating and quenching. The cut shows the 




Fig. 301. 



die with the stripper- attached. This is removed 
when the die is hardened. The screw holes should be 
filled with fire clay dough as it is not necessary to 
harden the walls of these, and the danger of cracking 
is reduced by so doing. As stated this die is made 
from thin stock (f). ^-S a result the top and bottom 
must be uniformly cooled or the die will spring. 
A bath made by dissolving 10 tablespoonfuls of salt 
to a gallon of water is used. The bath is kept as 
nearly as possible at a temperature of 80° F. The 



MISCELLANEOUS WORK. 



283 



die is immersed endwise and worked back and forth 
to force the Hquid through the opening and to cool 
both flat surfaces as uniformly as possible. The 
temper is drawn by heating in oil to 450° F. 

Fig. 303 represents a die that requires extreme care, 
and the display of considerable ingenuity in hard- 
ening as the thin partition between the openings 

stripper 



Die 





r~\ stripper /^ 


A 




.Die 



Fig. 302. 

cc is liable to break away from the body of the die on 
account of its hardening so much more rapidly than 
the heavier portions, and as the heavier portions 
would continue to contract after the partition was 
hard and unyielding. To overcome this tendency 
the walls of the partition should be covered with oil 
by means of a small brush just before immersing the 
die in the bath, thus retarding the hardening and 
consequent contraction at this point. The stripper 
plate screw holes and stop-pin hole should be plugged 



284 



FORGE-PRACTICE, 



with fire clay dough before the die is placed in the 
fire. 

Hardening Redrawing Dies. — Redrawing dies and 
other articles that must have an extremely hard sur- 
face on the walls of the hole, and where a soft exterior 
is desirable may be satisfactorily hardened by heating 
to the proper temperature, then enclosing in the fix- 
ture shown in Fig. 304 and allowing a stream of water 





Fig. 303. 



to run through the hole as shown. Do not allow the 
lower end of the fixture to enter any body of water as 
this would retard the fiow of the stream through 
the hole, steam would form and poor results would 
follow. 

Dies and other pieces having holes which go only 
part through them, whose walls must be hardened 
cannot be treated in a satisfactory manner unless 
some means is provided for forcing the liquid to the 
bottom of the holes. This is best accomplished by 



MISCELLANEOUS WORK. 



285 



running a pipe nearly to the bottom of the hole as 
shown in Fig. 305 where one piece of pipe is fitted 
over another thus enabling one to use the device 
where holes of varying depths are encountered. In 
hardening pieces of this kind steam is the principal 
obstacle to be overcome, the water going down into 
the hole forces the steam out, and at the same time 





Fig. 305. 



acts on the walls of the hole. When heating such 
pieces it is advisable to fill the hole with a mixture of 
4 parts powdered charred leather and i part table 
salt before placing in the furnace to prevent oxida- 
tion of the surfaces and render them perfectly clean 
and ready for the action of the liquid. 

In cases of the kind under consideration care should 
be exercised that the liquid does not enter the hole 



286 



FORGE-PRACTICE. 



under too great pressure. The pressure should be 
just enough to insure the removal of steam and to 
carry the water out before it heats to any extent. 

A die with a hole having two or more sizes as 
shown in Fig. 306 presents a problem that causes 
considerable perplexity at times. Unless the piece is 
heated in a manner that excludes all air from it, scale 
is apt to form, and while this scale might crack away 
and pass off with the liquid used in quenching if 

the hole was of one size, 
the scale in the corners 
formed by the change of 
size is not so easily gotten 
rid of and unless some 
method is devised for ' ' strik- 
ing" it, good results can- 
not be obtained. One 
method is to harden with a 
stream of brine, but many 
times, especially in the case of high carbon steel, 
brine may be considered too harsh. Another method 
is to run brine through the hole for a few seconds 
and then to immediately change to water as shown 
in Fig. 307. A method practiced with good results 
in one plant is to sprinkle a very small amount of 
powdered cyanide of potassium into the hole just 
before removing the die from the fire, then quench as 
shown in Fig. 304. 

Where the condition of the hole under considera- 
tion exists care should be used in determining the 
velocity with which the liquid is projected into the 
hole. The size of the stream and the velocity should 




Fig. 30b. 



MISCELLANEOUS WORK. 



287 



be graduated so that the water will not bound back 
and retard the water going into the hole or satis- 
factory results will not follow. In fact, the pre- 
caution just mentioned should be observed when 
quenching any die where the walls of the hole are the 
part desired hard. 



O 




f«Q 




Fig. 307. 



Burnishing Dies. — Fig. 308 shows a die used in bur- 
nishing the edges of a blank that had been pre- 
viously punched from sheet steel. Burnishing is 
resorted to where edges must be highly finished, and 
of accurate diameters, and also furnishes a means 
of doing the work at a greatly reduced price as com- 
pared with polishing. As the walls of the hole taper, 
being smaller at the bottom, an immense strain tend- 
ing to burst the die is given it. As a consequence 
the heat treatment must be such as to insure the 



288 



FORGE-PRACTICE. 



greatest possible strength. Forcing a blank through 
a hole smaller than its own diameter also sets up a 
tendency to maximum wear of the walls of the hole 
necessitating an extremely hard surface. Dies of 
this class must have the surface of the holes highly 
polished in order to effectually burnish the work. 
When the hole is machined somewhat smaller than 
finish size, and is ground and lapped after hardening 
no particular attention need be given to retaining 






Fig. 308. 



the finish of the hole, but where the working finish 
is given before hardening extreme care must be exer- 
cised to prevent even the slightest degree of oxida- 
tion. 

Summing up the conditions just mentioned we 
find that the die must be hardened so as to produce 
the maximum of hardness and strength with free- 
dom from oxidation. Work of this kind should 
always be enclosed in a box surrounded with a pack- 
ing material composed of equal parts of charred 



MISCELLANEOUS WORK. 



289 



leather and charcoal. Before placing in the box the 
walls of the hole should be coated with file maker's 
paste, which is made of charred leather, flour and 
salt, the exact proportions of which are given else- 
where. The die should be heated to a uniform red 
and hardened by running a stream of water through 
the hole. The die should be placed in a cage as 



MM' 




Fig. 309. 



shown in Fig. 309 after taking from the box and 
before quenching. As the walls of the hole and a 
small portion of the top are the only parts hardened, 
any alteration in the size of the hole is not probable. 
The outer portions not being hardened are extremely 
tough and will resist the tendency to burst from the 
strains incident to forcing the pieces through. The 
paste is an added precaution against oxidation and 
protects the surfaces until the die is acted on by the 



290 FORGE-PRACTICE. 

water. In one shop that has come to the writer's 
notice the die is rem ;ved from the cage after the 
surface walls are thought to have been sufficiently 
hardened and immediately plunged in light oil. 
In this way the outer portion is somewhat stiffened. 
I am inclined to the opinion that this is not a safe 
practice especially if the pieces to be burnished are 
heavy, as heavy or hard stock would require a deeper 
penetration of hardness than light or soft stock. 
Then again a great deal must be left to the judg- 
ment of the operator as to the exact time the piece 
should be plunged in the oil. 

-The object of using the packing material when the 
die is heated is to protect it from the action of the 
air, to secure uniform heating and to prevent decar- 
bonizing in any way. It is removed from the box 
as soon as it is uniformly heated to the proper tem- 
perature and quenched. 

Forming and Bending Dies. — For dies used in form- 
ing and bending sheet metal a somewhat higher tem- 
perature must be employed' than when hardening 
tools used in cutting, as the particular condition to 
be overcome is a tendency to sink or cave in, and not 
only is a deeper penetration necessary than is the 
case with cutting tools, but the interior structure 
must be stiff er to withstand the tendency to sink. 
This condition can only be brought about by a 
higher temperature which causes the necessary 
changes in the steel. 

Cutting or Dinking Dies.— Dies used for cutting 
leather, cloth, paper, etc., are called cutting, or dink- 
ing dies. They are many times made from ' ' backed 



MISCELLANEOUS WORK. 29 1 

steel, that is, the portion that bears the cutting edge 
is of hardening steel while the balance is of wrought 
iron. The two are welded together in the steel mill. 
When heating for hardening special furnaces, so 
designed that the cutting edge to the welded line is 
uniformly heated to the desired temperature are 
used in some shops. Many times a hard coal fire 
of fine coal is used in heating as the fire can be run 
so that a uniformly low temperature can be obtained. 
The cutting edge can be bedded down into the coals 
with no danger of overheating. When dipping, a 
bath of light oil or warm water is used. If cotton- 
seed oil is found to be too heavy a small amount of 
light mineral oil may be added to obtain the right 
consistency. In drawing the temper of cutting dies 
the material to be cut must determine the amount of 
drawing. The range, however, is generally from a 
brown to a dark blue (500° to 570° F.). 

Curling Dies. — Curling and wiring dies and punches 
as shown in Fig. 310 should be quenched with their 
working faces uppermost, and by having a stream 
of water running down onto them. As such dies 
and punches are not, as a rule, made from steel con- 
taining a very high percentage of carbon they 
require a somewhat higher temperature than tools 
made from high carbon steel. As repeatedly stated 
the steel should not be overheated but simply given 
the proper temperature for desired results. 

Taps. — As this class of tool has its cutting portions 
in the form of slender projections extreme care should 
be exercised when heating for hardening or the 
teeth will become overheated before the body of the 



292 



FORGE-PRACTICE. 



tool reaches the desired temperature. A very good 
practice is to have a number of pieces of gas pipe 
somewhat larger and longer than the taps. Each 
tap may be placed in a pipe before it goes into the 
furnace. When heating as described there is less 
danger of overheating the teeth. A practice fol- 
lowed in some shops where screw die hobs are hard- 




FiG. 310. 



ened in quantities is to fill the teeth with the "file- 
maker's paste" described elsewhere. When the 
paste dries the hobs are placed in pipes and heated. 
While taps can be hardened in a still bath of brine, 
or water, better results follow the use of one of the 
type shown in Fig. 278 as the liquid is forced between 
the threads, thus insuring uniform cooling. Taps 
should not be quenched in very cold baths as a tem- 



MISCELLANEOUS WORK. 293 

perature of 70° to 80° F. gives better results. Taps 
larger than 1" diameter should be taken from the 
bath shortly after "singing" ceases and cooled in oil. 
While the temper of taps may be drawn to color 
more uniform results follow if an oil drawing furnace 
is used. If the temper is to be drawn to color the 
surface of the flutes may be brightened by grinding 
with some form of abrasive wheel making sure that 
a small amount is ground off the face of the cutting 
teeth. This is necessary as this surface is liable to 
contract in hardening more than that immediately 
back of it where there is sufficient stock to prevent 
contraction ; as a result the cutting edge of the tooth 
is slightly lower, and while this amount is very small 
it is sufficient to cause the tap to bind when cutting, 
especially if it is used on metals where it cuts very 
close to its own size. 

The temper to which taps should be drawn varies 
with the size and the use to which they are to be put. 
Those used for sizing, and which remove but a very 
little stock are sometimes left as they come from the 
hardening bath, more often though they are drawn 
to a pale yellow (430° F.). For ordinary use they 
are drawn to 450° to 460° F. Small taps used in 
screw machines are many times drawn to a brown 
yellow (500° F.), or to a light purple (530° F.), de- 
pending on the strains they are to receive. If quench- 
ing is necessary to keep the temper from running 
too much, warm oil should be used. 

Steel for Taps. — In most small shops and also in 
some of considerable size a certain "temper" of 
crucible tool steel is used for most cutting tools. 



294 FORGE-PRACTICE. 

While this practice does away with the mixing of 
various grades and the annoyance caused thereby, 
mixing is not necessary and seldom happens where 
a system of marking and keeping in separate racks is 
employed. 

Maximum results follow the use of steels suited for 
the individual tool, or for tools to be used for a cer- 
tain class of work. While "straight" carbon steels 
containing the proper peicentage of carbon give good 
results on some classes of work, certain of the alloy 
steels give very much better results on other classes. 
For instance, i.i to 1.25 per cent carbon gives fair 
results when used for taps to work on brass and cast 
iron, yet a steel of this same carbon content with an 
addition of 2.0 per cent tungsten will under the same 
conditions do many times the amount of work. 
This addition of tungsten, however, calls for a higher 
hardening heat; the makers recommending 1525° F. 

Vanadium steel made especially for taps, etc., 
gives excellent results so far as strength is concerned 
and is to be recommended where a slight change in 
pitch is not a serious matter. Straight carbon and 
tungsten steels when properly treated generally 
contract in length, but this contraction can be antici- 
pated when the tool is threaded, but vanadium steels 
may either contract or expand and for this reason 
cannot be used where accuracy of pitch is essential. 

Taps that are pack hardened do not, as a rule, 
change in pitch if the blanks are properly annealed 
and low heats are obtained when hardening. 

High speed steel is especially suited to tap making, 
especially for those used on screw machines. It 



MISCELLANEOUS WORK. 



295 



should be heated to about 2150° F. for hardening. 
In tempering they should be drawn to form 500° to 
950° F. according to size and the shock they are to 
receive when in use. 

Threading Dies. — Threading dies are made from a 
variety of steels. This is necessary on account of 
different demands on the tool resulting from the 
variety of metals to be threaded, and the opinions 
of men in charge of work. When the metal to be 
threaded is easily machined and free from grit, 
almost any good tool 
steel oi the proper carbon 
content gives good re- 
sults if properly treated. 
In shops where the screws 
are made from iron wire, 
or from stock that, on 
account of its composi- 
tion, 01 from other 
causes, subjects the die 
to abrasive action, it 
is many times advisable to use a suitable alloy 
steel that will resist the tendency to wear from the 
causes mentioned. If alloy steels are used the 
treatment must correspond to the requirements of 
the metal; however, instructions usually accompany 
steels that require special treatment. 

Threading dies are made in a variety of forms. 
The ordinary round, or button die shown in Fig. 311 
is made either solid or adjustable. If a solid die is 
to be hardened the chief requirement is suitably 
hardened threads, this hardness extending out into 




Fig. 311. 



296 FORGE-PRACTICE. 

the body of the tool for a distance that insures good 
results. In some shops it is customary to harden 
the whole die to as uniform a degree as possible and 
then draw back the portions that should not be as 
hard as the cutting portions. In other shops it is 
considered best practice to harden the threaded 
portions and for a distance out into the die leaving 
the balance soft, while the requirements in other 
places make it necessary to harden the portion just 
mentioned and stiffen the balance of the die in oil. 

As the threaded portion is the essential part of 
the die, and as most "button" dies are so made that 
either end may be used in cutting, it is apparent that 
an equality of hardness throughout the threaded 
hole is necessary. This result can be accomplished 
by immersing the die edgewise in a still bath of brine 
workmg back and forth to force the liquid through 
the hole. If the outer portion is desired soft the 
die may be held in a fixture so constructed that the 
portion desired soft is covered. 

Milling Machine Cutters. — Probably no one class of 
tool is a source of greater anonyance to the hardener 
than the cutters used on milling machines and gen- 
erally known as "mills." The troubles experienced 
should not, in all cases, be attributed to the hard- 
ener. This form of tool is costly to produce and in 
many factories is used in large quantities. Effi- 
ciency is many times based on the length of life of the 
tool regardless of the quantity of work produced, 
and this has led to the use of slow speeds and fine 
feeds, where, under different conditions, namely, 
maximum speeds and feeds for properly designed 



MISCELLANEOUS WORK. 297 

tools, those considered would have been found sadly 
wanting and the hardener blamed because they 
would not do the things easily accomplished by 
properly designed tools hardened, and tempered 
exactly as these were. A mill with a great number of 
fine teeth where but few are required collects chips 
between its teeth and if coarse feeds are resorted to 
the teeth will break. As the cooling liquid cannot 
have free access to the teeth slow speeds must be 
resorted to or heating will result. If the mill is run 
at a high speed, which, under right conditions, would 
be easily possible it will heat and the temper will be 
drawn to a point that causes rapid dulling of the 
teeth, consequently, as the tool is too soft, and the 
teeth are too weak to stand up, the fault is usually 
put up to the hardener, and he, poor fellow, knowing 
nothing about tool design, does not know what to do 
to bring about correct results. The writer has seen 
mills having forty cutting teeth, which were being 
used in milling a semi-circular groove through a piece 
of work, that had to be run at a speed and feed that 
made it impossible to produce more than 30 pieces 
in ten hours. These were replaced by others made 
from steel of the same make and "temper," which 
contained 7 teeth and produced 125 pieces in the 
same time. Both were hardened and tempered by 
the same man and as nearly as possible in the same 
manner. 

Slender teeth are conducive to weakness. Cutter 
teeth should always be made of a shape that insures 
maximum strength because if a tooth springs it 
cuts deeper into the work than it should, thus put- 



iZgS FORGE-PRACTICE. 

ting a breaking strain on the tooth. If the angle 
at which the tooth is backed off in grinding is not 
exact, trouble will follow. If it is backed off too 
much, the fine cutting edge does not receive the 
support it should and as a result flaxes off, or, on the 
other hand if it is not given sufficient angle the heel 
will rub, thus causing the tool to heat and dull 
quickly. These are conditions that the hardener is 
in no way responsible for, yet, unfortunately, he is 
many times scored for these and similar troubles, 
the cause of which he is entirely ignorant. 

The writer's attention was called, a short time ago, 
to a batch of slotting mills made from a well-known 
brand of tool steel. These mills were to be used in 
cutting slots I" deep in 0.30 per cent open hearth 
steel forgings that were, well annealed. Several of 
the mills were tried, but could not be made to work 
as they would dull quickly and could not be forced 
into the stock. Examination showed that they were 
not given sufficient angle in backing off the cutting 
edges. After being reground to the proper angle 
they were pronounced highly efficient. In this case 
the opinion of those in authority had been divided, 
by some the hardener was considered at fault, while 
others claimed the steel was unfit for the purpose. 
The incidents mentioned in connection with milling 
cutters are characteristic of troubles that are met 
with frequently in many shops. If the cause of 
the trouble is not discovered what is more natural 
than to lay it to the steel, or the hardener. 

If the hardener is blamed for troubles that orig- 
inate outside of his department, and he hasn't suf- 



MISCELLANEOUS WORK. 299 

ficient knowledge of tool design to enable him to 
locate the trouble, he naturally changes his method of 
treatment of that class of tool with results that are 
not to his credit. Troubles of the character just 
mentioned are not peculiar to milling cutters, but 
undoubtedly are of more frequent occurrence with 
this class of tool than any other. 

Steel for Milling Cutters. — Milling cutters are made 
from steel containing all the way from i.oo to 1.60 
per cent carbon. It may also contain varying pro- 
portions of tungsten and other elements. The vary- 
ing proportions of these elements necessitates a vari- 
ation of temperatures when heating for hardening in 
order to secure the best possible results. 

Hardening. — The size and design of the tool also has 
a bearing on the hardening temperature. Extreme 
care should be exercised, when heating, that the teeth 
do not become overheated before the body of the tool 
has reached the desired temperature, which must be 
uniform throughout the piece. Should any portion of 
any piece being heated for hardening become overheated 
the piece should be removed from the fire and allowed to 
cool, after which it may be reheated and hardened. 
Although muffle furnaces are not generally used at 
the present time, on account of the comparatively 
high cost for fuel and maintenance, they afford an 
ideal method of heating tools of the character under 
consideration. In the absence of a muffle furnace 
the mill may be heated satisfactorily in an ordinary 
oven furnace by placing over it a piece of sheet iron 
bent so as to prevent the direct action of the heat. 
This protecting piece should not lie directly on the 



300 FORGE-PRACTICE. 

work, but should be far enough from it so that the 
heating will be from radiation. It is a good plan to 
surround the teeth with dry fire clay or some refractory 
material during the first stages of the heating to 
retard the action of the heat at these portions until 
the body of the tool has reached a low red when it 
may be raised and the material spread over the floor 
of the chamber and the mill allowed to rest on it. 
The mill should be turned over and around occa- 
sionally as it commences to get red to 
insure uniform heating. Toward the 
latter part of the heating operation 
it is well to raise the tool from the 
floor of the chamber by means of 
several small pieces of fire brick, that 
have been heated in the chamber 
thus allowing the heat to circulate 
around all parts of it. Tongs should 
seldom or never be used when quench- 
ing a mill as they prevent the water 
"~^ having free access to every part. A 
Fig. 312. hook of the design shown in Fig. 312 

answers the purpose very well. If a 
still bath is used long cutters should be immersed 
lengthwise and worked up and down and around in 
the bath, first in one direction then in another, alter- 
nating the movement frequently. If a bath of the 
design shown in Fig. 278 is used, where the liquid is 
projected uniformly against the teeth it is only nec- 
essary to work them up and down slowly to cause 
the liquid to pass through the hole. Thin mills 
should be dipped vertically to prevent springing, 



MISCELLANEOUS WORK. 



301 



as shown in Fig. 313. A method employed by one 
very successful hardener when dipping thin mills 
consists in dipping vertically then rotating the mill 
slowly by means of a piece of wire thus bringing it 
constantly in touch with agitated water. Another 
method , employed in a shop where many slotting 



r^ 





Fig. 313. 



Fig. 314. 



cutters, of from |" to 5" thicknesses are made, con- 
sists of immersing in a bath of water having a supply 
pipe bent in the form of a circle as shown in Fig. 314. 
Numerous small holes are drilled on the inner por- 
tion of the circular pipe to project small streams 
toward a common center. The mill is held so that 
these streams will impinge against the teeth. 



302 FORGE-PRACTICE. 

Mills that are |" or more in length should be kept 
in the bath until the "singing" incident to the im- 
mersion of red-hot steel in water ceases and then be 
plunged into oil and left until cold. While some 
hardeners gauge the time of singing by the ear, it is 
better practice to gauge it by the vibration trans- 
mitted through the hook used in holding the piece, 
to the hand. A few seconds after this ceases the 
mill should be transferred to the oil. The oil bath 
should be conveniently near the first quenching bath 
so that there will be very little time lost in transferring 
from one to the other as it is never safe when quench- 
ing to allow the contraction of the metal to stop and 
expansion to set in. The process of contraction 
should be constant from the time the steel is im- 
mersed until it is cold. 

Mills that are |" or more in length should be 
heated to relieve the hardening strains as soon as 
taken from the oil. This may be done by holding 
over a blaze; keeping the mill revolving all the 
time and thus uniformly heating until a particle of 
moisture placed on the piece steams. If the temper 
is to be drawn by color, time can be saved by bright- 
ening the backs of several of the teeth and finishing 
the tempering operation at this time. Mills made 
from ordinary carbon steels and used for ordinary 
lines of work are tempered to a light straw color 
(430° F.). 

If a quantity of mills are to be tempered, time will 
be saved and more uniform results obtained if they 
are drawn in an oil-tempering bath and the tempera- 
ture gauged by a thermometer. In this way absolute 



MISCELLANEOUS WORK. 303 

uniformity of temper may be obtained, which is 
quite impossible where tools of irregular contour of 
ununiformity of size are treated by the color method. 

If the mill must be tempered to color, a very com- 
mon method consists in drawing on a heated plug. 
While this gives good results in cases where extreme 
care is exercised, it is a source of a great deal of 
trouble at times, especially in the case of large mills 
and those having large and small sections adjacent 
to one another. If the plug is to be used the mill 
should have several teeth brightened on their backs. 
It should then be held over a fire and heated until 
lard oil placed on the teeth commences to smoke. 
The mill may now be placed on the plug which has 
been heated almost to a red, and revolved. The 
brightened surfaces should be closely watched, when 
they show a light straw color it should be plunged 
into warm oil, but never into cold water. 

Let us return for a moment to the subject of baths 
used in quenching milling cutters. The one most 
commonly used is clear, cold water. Right here we 
may get into trouble as extremely cold baths should 
seldom or never be used when hardening this class 
of tool. There are few cases where the water should 
be below 60° F. and many cases where 70° F. will 
give better results. The bath, however, should be 
of generous proportions, especially if it has no means 
whereby a constant supply of liquid is being fed into 
it. If it is provided with a supply pipe, this should 
have a steam pipe entering it so that the incoming 
water can be brought to the proper temperature 
before coming in contact with the work. A ther- 



304 



FORGE-PRACTICE. 



l!|mini]i|iill|i!l|imiiiii!immmmi]|!., 



rJ^i^ater- 



mometer should be kept conveniently near in order 
that right temperatures can be readily obtained. 
Both the inlet and steam pipes should be provided 
with valves in order that the desired amount of 
liquid and the proper temperature may be had. 

If brine is considered the proper quenching medium 
the bath may be provided with a storage tank and 
pump and a constant supply of this liquid of any 
desired temperature may be had. If oil hardening 
steels are used in making the mills a bath having a 

constant supply of oil of the 
proper temperature may be 
used. Both the oil and brine 
baths are illustrated and 
described under "Baths." 

Many hardeners use a bath 
of water or brine with an inch 
or two of oil on the surface 
as shown in Fig. 315. The 
red-hot steel passing through 
the oil takes a thin coating of 
oil which prevents too sud- 
den action by the lighter liquid underneath. This 
form of bath has been used by the writer for a num- 
ber of years on certain classes of work, especially 
where the teeth of mills were cut with a sharp- 
pointed cutter. The oil lodging in these sharp cuts 
prevents the rapid action incident to a lighter fluid 
acting directly at these points. 

Thin Cutters. — Screw slotting cutters, slitting saws 
and other forms of very thin cutters are hardened 
very nicely between flat plates. These plates may 



Fig. 315. 



MISCELLANEOUS WORK. 305 

be so arranged that when the cutter is placed be- 
tween them they will submerge in oil or water, or 
in the case of medium thin cutters the faces of the 
plates may be smeared with oil, or in the case of 
very thin cutters the plates alone will absorb the 
heat fast enough to produce desired results. Where 
but a few cutters are hardened at a time ordinary 
bench plates of convenient size may be used. This, 
of course, necessitates the services of two men, the 
hardener and a helper. Where the work is done in 
large quantities such practice would prove costly 
and a special device where the movable plate is 
operated by the foot may be employed, thus making 
it possible for one man to tend to the heating of the 
cutters and to operate the plate. 

Troubles. — In an experience of over twenty years 
in looking into other peoples' troubles the writer has 
found that as many, if not more, difficulties are 
encountered by hardeners in treating milling machine 
cutters, as any class of cutting tool. Most of these 
troubles are directly traceable to comparatively few 
causes. The most common cause is ununiformity 
in heating. As previously stated, a piece of steel 
that is not uniformly heated is bound to cause trouble 
when it contracts in the operation of hardening. If 
any portion of a piece has been overheated and then 
allowed to cool in the furnace to the temperature of 
the balance of the piece, that portion has the same 
structure internally as would have been the case 
had it been hardened at that heat, and on account 
of this difference of grain structure cracks are liable 
to result. Improper handling when in the bath is 



2p6 FORGE-PRACTICE. 

more common than is generally known. In order 
that steel may harden satisfactorily it is necessary 
that it should contract uniformly. This, in the case 
of cutters of irregular shapes, means skillful handling 
in the bath. High heats are a source of more or less 
trouble, but not so frequently encountered at the 
present time as a few years ago on account of the 
better knowledge hardeners have of the effect of 
high heats on steel. Underheating is often found to 
be a source of trouble not generally considered as a 
piece of steel may be hardened so that it will be file 
hard and yet not be in condition to cut other metals. 
While steel should not be heated any higher than is 
necessary to produce desired results, it must be 
brought to the right temperature to get these results. 
Draw Broaches. — This form of tool, if made from 
straight carbon tool steel should be hardened at a 
temperature that insures the greatest possible tensile 
strength, as the tendency is to pull apart when in 
use. As much trouble is experienced from insuf- 
ficient chip space between the teeth, as from im- 
proper hardening. This is a defect over which the 
hardener has no control, and ignorance of the cause 
of the trouble may lead to constant changes in meth- 
ods of treatment until the hardener loses confidence 
in his own ability. Very many forms of cutting 
tools show remarkable ability to stand up and retain 
a keen cutting edge when pack hardened, but draw 
broaches to be used for heavy cuts do not stand up as 
well as when heated in a tube and plunged in a light 
oil to which has been added a small amount of alum 
or borax, preferably the former. Larger broaches 



MISCELLANEOUS WORK. 307 

are usually quenched in luke warm water which 
has a thin coating of light oil on the surface, and the 
temper drawn to a full straw. 

Rivet Sets. — The excessive strain and wear to 
which rivet sets are subjected renders necessary the 
exercise of extreme care in heating and quenching, 
and also a considerable display of ingenuity, at times, 
to determine the best method to pursue to get de- 
sired results. 

Experiments are many times desirable, especially 
when using the so-called alloy steels to determine the 
exact heat treatment necessary to 
obtain good results. Steel makers' 
instructions regarding temperatures 
best suited to desired results are not 
always to be relied on when the steel is 
used for some specific purpose entirely 
out of the range anticipated by the 
steel maker. The writer recalls one 
particular steel that was used for rivet 
sets. This steel when hardened at -p^^ ^^ 
the temperature called for in the 
instructions on the bar did not show even average 
results. When heated 150° F. higher, or to 1500° F. 
it gave remarkable results. 

When quenching it is advisable to rest the sets on 
the plain end and send a stream of water directly 
into the impression as shown in Fig. 316. 

Large Rings. — When heating large rings and sim- 
ilar pieces for hardening it is necessary to have a 
suitable furnace or satisfactory results cannot be 
obtained. Fig. 317 shows a gas-burning furnace espe- 




3o8 



FORGE-PRACTICE, 



cially designed for such pieces. This furnace being 
round in form will heat a round piece more uniformly 




Fig. 317. 

than one rectangular in form unless extra precautions 
are taken with the latter. 



MISCELLANEOUS WORK. 309 

If it is necessary to use an ordinary case hardening 
furnace a piece of sheet steel, or sheet iron several 
inches larger each way than the piece should be 
placed on the floor of the furnace, on this should be 
several pieces of iron all of a uniform thickness, for 
the ring to rest on. After being placed in position 
the ring should be covered with granulated charcoal 
or with a mixture of charcoal and charred leather 
and gradually heated to a full red. The heating 
must not be carried on any faster than is consistent 
with a uniform temperature throughout the piece. 
If many pieces of a size are to be hardened it is 
advisable to make iron boxes several inches larger 
each way than the ring. The boxes should be pro- 
vided with covers. In the bottom of each box place 
several inches of granulated charcoal; on this place 
the ring, filling the box with the packing material. 
After the cover is in position the box may be placed 
in the furnace and the ring gradually heated to the 
desired temperature. 

As the red-hot ring would go out of shape if held 
in any but a horizontal position, and as all portions 
are desired hard, it is necessary to provide a special 
holder for use in dipping in the bath. This holder 
should be so designed that water can have free access 
to all portions of the ring. The supporting parts of 
the holder should be worked nearly to a sharp edge 
so as not to retard the action of the water. 

The bath should be of the design shown in Fi \ 278 
having jets from the bottom and top and pipes up 
the sides to force water against the circumference 
of the ring. When the piece has cooled throughout 



3IO FORGE-PRACnCE. 

to the temperature of the water it may be removed 
from the bath and immediately heated to remove 
hardening strains. While this heating is going on 
the piece may be brightened and the temper drawn 
the desired amount. 

Spring Threading Dies. — Spring threading dies, 
hollow mills and similar tools having holes running 
through them, or part way through them, and whose 
cutting portions are on the end should be quenched 
in a bath of brine with the cutting end up to allow the 
steam to escape readily. They should be worked 
up and down in the bath to force the liquid to all 
portions of the hole. 

For most work the cutting portions should be 
drawn to a full straw color (460° F.) and the balance 
drawn to a blue. 

Spring Tempering. — Such articles as springs, screw 
drivers, etc., are hardened and tempered in such a 
manner that if bent they will return to their original 
shape when the strain is removed. 

Small articles are usually hardened in oil prepara- 
tory to spring tempering, as water would cause 
brittleness that could not be done away with in the 
tempering process. Medium-sized pieces are many 
times hardened in warm, or even hot water, while 
extra large ones may be hardened in warm or luke- 
warm water. 

The object of the hardening process in spring 
tempering is not to produce actual hardness, but 
stiffness, and the less brittleness produced by the 
operation, the better. Steel hardened in oil is much 
tougher than if hardened in water and it is advisable, 



MISCELLANEOUS WORK. 31I 

whenever possible, to use oil, even though it is neces- 
sary to add some substance to it. 

P'or most purposes special grades of spring steel 
give better results than tool steel. A good grade of 
open-hearth steel containing from .40 to .80 per cent 
carbon, if made into springs, will prove more satis- 
factory than a grade of tool steel costing five times 
as much. 

In the selection of steel for springs to be subjected 
to but little strain almost any good grade of spring 
steel will answer. If, however, it is to be subjected 
to very rough, hard usage it is best to obtain directly 
from the steel maker the necessary information 
regarding the exact grade needed unless the user has 
had education or experience that enables him to 
rightly decide as to the quality needed. 

When heating for hardening employ the lowest 
heats possible consistent with good results. As 
spring steel contains less carbon than ordinary tool 
steel it may be necessary to heat it a trifle hotter to 
obtain satisfactory :cesults. This should always be 
determined by experiment before going ahead with a 
batch of work. 

The nature of the spring must determine the char- 
acter of the bath. For ordinary purposes sperm oil 
works well, at other times a good grade of lard oil, 
cotton-seed oil, fish oil or some of the commercial 
hardening oils may be found to answer the 
purpose. 

It is necessary sometimes to add certain ingre- 
dients to the oil to obtain desired results. The 
following formula is used by a manufacturer who 



312 FORGE-PRACTICE. 

makes large quantities of springs about the size of 
ordinary clock springs: 

Sperm oil 15 parts 

Beef tallow 2 parts 

Resin i part 

At times it has been found necessary to add a piece 
of bee's wax to the above to prevent a granular con- 
dition in the hardened steel. 

Some hardeners use turpentine in place of resin 
in the above formula. Its use is not to be advocated 
unless extreme care is exercised as it is highly in- 
flammable and serious bums may result. 

Springs should never be heated in a furnace where 
oxidation of the surface takes place, as this oxidation 
may assume the form of blisters that would prevent 
the contents of the bath coming in intimate contact 
\\ith the steel at those portions, and would result in 
soft spots that would be fatal to the spring. Resin in 
the bath has a tendency to strike any ordinary scale ; 
but, it is best to do away, as far as possible, with 
oxidation. 

Drawing Temper. — If but a few springs are tem- 
pered at a time, the temper ma}^ be dra\^Ti by heating 
until tallow, sperm or lard oil will catch fire (flash) 
from the heat in the steel. To determine this the 
spring must be removed from the fire when the oil 
on its surface starts to bum; if it continues to bum 
when away from the heat of the fire it has absorbed 
sufficient heat, if not, it should again be heated. 
Very heavy springs may have the oil flashed off two 
or even three times. The method just described 



MISCELLANEOUS WORK. 313 

answers when the steel from which the springs are 
made contains a fairly high percentage of 
carbon. 

When low-carbon spring steels are used flashing 
cannot be resorted to as it leaves the springs too soft. 
In such cases they must be brightened and the tem- 
per drawn by color. The exact temper color can- 
not be stated arbitrarily as the carbon content of 
the steel must determine this, but usually it ranges 
from a light blue to a dark blue. 

When work is done in quantities it is always best 
to place the pieces in a perforated pail which is 
immersed in a kettle of oil over a fire and the whole 
heated until the right temperature is reached. 
This is determined by means of a thermometer. 
The kettle should be so designed that a cover may be 
placed on it in case the oil catches fire. The cover 
should be provided with a long handle, in order that 
the operator will not be burned when putting it in 
position. It should be made high enough to receive 
the thermometer. 

It is advisable to leave the thermometer in the 
oil and allow it to cool with the oil. If it is neces- 
sary to remove the thermometer place it where no 
draft of air can strike it, as sudden changes of tem- 
perature will cause the glass to crack. 

Certain forms of springs are heated in a crucible 
of melted salt for hardening, while others are heated 
in melted glass. These provide excellent mediums 
for uniformly heating springs of unequal size in the 
various portions. 

Heavy springs and screw drivers are tempered at 



314 FORGE-PRACTICE, 

times by heating in the fire and gauging the tempera- 
ture by drawing a hard-wood stick or a hammer 
handle across a corner of the piece. If the shaving 
removed catches fire from the heat in the steel fur- 
ther heating is unnecessary. If there is a liability of 
the piece being heated too much, it may be checked 
when it reaches the proper temperature by plunging 
in warm oil. 

Second Blue. — Springs made from high-carbon spring 
steel and tool steel are sometimes tempered to the 
second blue. This is done where the rich blue 
appearance is desirable when the springs are located 
where they can be seen on exhibition machines. To 
accomplish this the springs are polished after hard- 
ening, placed in a pan of sand and shaken over a 
fire until the proper temper color appears. The 
colors will show as stated in the Temper Color Chart. 
After the colors have all appeared as set forth the 
surface assumes a gray color followed by a blue 
which is called the second blue. When the second 
blue appears the spring should be immersed in warm 
oil to prevent the temper going too far. 
J The writer has found prolonged heats to be a 
common cause of poor results in hardening springs. 
Such heats not only tend to oxidation but also 
weaken the steel. The practice of raising a furnace 
to a given temperature and then allowing the springs 
to soak in the fire until they reach the furnace tem- 
perature cannot be condemned too severely. Any- 
one can convince themselves of the truth of this 
assertion by heating two springs, one by a method 
that insures uniform temperature as rapidly applied 



MISCELLANEOUS WORK. 315 

as possible, and the other by soaking, then testing 
in comparison with one another. 

A manufacturing concern condemned some 0.60 
per cent carbon spring steel being under the im- 
pression that it would not harden. Investigation 
showed that this steel was heated in a furnace with a 
temperature of nearly 1500° F., the springs being 
left in until they were of the same temperature as 
the furnace. Another batch heated quite rapidly 
and only exposed to the heat for about one-quarter 
of the customary length of time and quenched at a 
lower temperature hardened perfectly. When the 
temper was drawn these springs met every demand 
in the testing. As these springs had to stand very 
heavy strains the tests were correspondingly severe. 

As in annealing prolonged heats in hardening 
should always be avoided as they change the struc- 
ture of the steel and render it unfit for use. 

Drop Forging Dies. — Drop forging dies, when 
made for general work, tax the ingenuity and 
resourcefulness of the hardener to a degree not experi- 
enced with any other class of tool. As they must be 
treated so as to produce a hard face and a depth of 
penetration sufficient to prevent sinking when in use 
the problem becomes difficult in proportion to the 
intricacy of the design of the impression and the 
resistance of the stock to be forged. The producing 
of the necessary hardness and penetration without 
warping the die complicates the problem. Forging 
dies are of two general classes, namely hot forging 
dies and cold dropping dies. The former in shops 
doing general jobbing work are generally made from 



3l6 FORGE-PRACTICE. 

open hearth steel containing 0.60 to 0.80 per cent 
carbon. In other plants they are made from cru- 
cible steel containing about the same proportion 
of carbon. 

Cold dropping dies are usually made from crucible 
steel containing a higher percentage of carbon in 
order to obtain a deeper penetration and a stiffer 
backing to the bottom of the impression as the ten- 
dency to sink is greater where cold metal is struck. 
All portions of a die block that are to be machined 
should first be rough machined then thoroughly 
annealed before the impression is finished and the 
tang machined to size. This annealing heat should 
be about 50° F. higher than the heat employed in 
hardening. 

In shops where the volume of business warrants 
the outlay continuous furnaces are used in heating 
the block for hardening. These furnaces are so 
designed that the portion where the die enters is 
not very hot, while the portion at the opposite end 
and where the die leaves the furnace is of the tem- 
perature the die is to be heated. The use of this 
furnace, of course, insures ideal conditions. Such 
furnaces, however, are not in general use and the 
hardener in the average plant finds it necessary to 
produce satisfactory results by the use of an ordinary 
furnace. This can be done by the exercise of ingenu- 
ity and extreme care. When possible the die should 
be placed in the furnace before it is heated very 
much and the temperature raised gradually to pre- 
vent overheating of the edges and corners. 

Dies should be placed in shallow boxes with the 



MISCELLANEOUS WORK. 



317 



face embedded in charred leather, or animal char- 
coal. To accomplish this a layer of one of these 
materials about 2" deep should be placed on the 
bottom of the box and the face of the die laid on 
this. The box should be filled with the packing 
material extending up at least \" beyond the depth 
of the impression. Where a general line of work is 
done it is necessary to have boxes of various sizes 
and depths to satisfactorily accomplish the desired 
results. The writer has advocated for years filling 




Fig. 318. 



in the sides of the tang with fire clay dough as shown 
in Fig. 318, and placing a layer of the same on top of 
the tang, also, as shown. This prevents the hot 
gases acting, directly on the steel at these portions. 
Many experienced hardeners do not consider this 
necessary, but results have proven this precaution 
to be of value entirely out of proportion to the 
expense involved, which is slight. The furnace 
should be heated gradually, and at no time should 
the temperature be allowed to exceed the tempera- 
ture to which the die is to be heated, or some portion 
will become overheated and cracks will result. 



3i8 



FORGE-PRACTICE. 



In order to successfully harden dies of this char- 
acter a bath adapted to the work must be used. 
It is folly to attempt to obtain good results unless 
a plentiful supply of water that can be projected 
against the die is available. A form of bath that 
gives excellent results is shown in Fig. 319. It will 
be noticed that the overflow pipe is telescoped in 
order that any desired level of water may be main- 
tained in the bath as this should be somewhat above 




Fig. 319. 

the deepest part of the impression when the die is 
face down in the bath. 

In some shops it is customary to partially harden 
the tang before hardening the face. This tends to 
prevent the die from springing when the irregular 
surface of the face is hardened and is done by placing 
the die on the supporting wires in the bath with the 
tang down, then opening the valve in the supply 
pipe and allowing the water to play against the tang. 
The overflow pipe should be adjusted so that the 
contents of the bath will come about 1" up the body 



MISCELLANEOUS WORK. 319 

of the die. The water should be allowed to play 
against the tang until the red has disappeared from 
the portion under water, then the position of the die 
is reversed and the flow of water is allowed to come 
against the face. In the meantime water should be 
poured from a dipper or some convenient retainer 
onto the tang to keep it from drawing back until the 
surface of the face is below a red. When the face 
has lost every trace of red cease turning water on the 
tang and allow the red in the body of the die to work 
back through the tang. When the die has cooled to 
the temperature of the bath it may be removed and 
heated to remove hardening strains. There are 
several methods of doing this. One method consists 
in placing in a continuous furnace timing the travel 
of the die so that it will reach a temperature of 250° 
or 300° F. as it comes out. It may then be taken 
to the tempering fire and the heating process con- 
tinued until the temper is drawn the right amount, 
if it is necessary to temper it further than removing 
strains. Another method consists in taking directly 
from the bath to the tempering fire and relieving 
strains there. This is an uncertain method as the 
die, unless turned frequently, is not heated uniformly 
and if the heat enters one portion while the balance 
of the block is cold and unyielding it is very apt to 
break. 

A method employed with very good results in a 
number of hardening plants is to place the die in a 
steam box on wire rods. When the box is closed 
steam is turned on and the die is gradually brought 
to a temperature of 212° F. 



320 FORGE-PRACTICE. 

Another method is to have a tub of water with a 
steam pipe entering at some convenient point. The 
die is placed in the water, the steam turned on, and 
everything brought to the boihng point. The boil- 
ing is kept up until the die is uniformly heated. 
It is a mistake to immerse dies of intricate design, or 
with projecting portions from the face directly into 
boiling water as is sometimes done, as the slender 
portions when subjected to the high temperature 
expand faster than the balance of the piece and, as a 
result, are cracked or broken off. 

When hardening dies having projections from the 
face, or which have delicate portions that would be 
liable to crack from the unequal contraction in the 
bath, it is a good plan to cover such portions with 
heavy oil, or soap just before immersing in the hard- 
ening tank, making sure that there is a generous sup- 
ply of the substance at the point where the pro- 
jection joins the block. This will retard the harden- 
ing at these points thus producing a more uniform 
contraction. The water from the supply pipe will 
wash the oil or soap away in time to produce suffi- 
cient hardness. 

A method of quenching employed at times neces- 
sitates the use of a bath of the design shown in Fig. 
320. In this case the die is lowered into the bath 
until it rests on the supporting wires with the tang 
well back toward the wall of the tank. The jets of 
water playing against the face cools it very nicely. 
In the case of dies with impressions that might cause 
steam to pocket in them this form of bath works 
well as the steam can readily escape. 



MISCELLANEOUS WORK. 



321 




U^ 



Fig. 320. 



li\ 



/////.'/./iiiiiiunww 



Mik 



^ 



Another method is to lay the die on wires in a tank 
from which the water can 
escape without coming up 
around the die and from 
an overhead pipe allow 
the water to play against 
the face which is, of 
course, uppermost as 
shown in Fig. 321. 

The writer is inclined 
as a result of experience 
to favor the first method 
described for the majority 
of work. Realizing, how- 
ever, that there are cases 
where special methods of quenching must be resorted 
to to accomplish certain desired results. 



lo-" 



Fig. 321. 



322 FORGE-PRACTICE. 

Dies from some of the alloy steels may be hardened 
in oil ; certain of the steels require oil hardening, but 
in such cases instructions accompany the steel stating 
the exact treatment it should receive. To attempt 
to describe these various methods would be a need- 
less waste of time. 

When worn dies made from straight carbon steel 
are to be annealed and re-worked, the double anneal- 
ing process is sometimes resorted to with good re- 
sults. The dies are first heated to a temperature 
75° to 1 00° F. higher than the hardening heat and 
allowed to cool. They are then heated to a tem- 
perature slightly lower than for hardening. Some 
hardeners claim that dies heated in this way are less 
liable to go to pieces when hardened. 

Reworked dies should have sufficient stock re- 
removed from the face to get beneath the portions 
that are ruptured as a result of the compression due 
to the constant shocks received when in use. 

Causes of Trouble. — To attempt to enumerate 
all the reasons for troubles experienced when treat- 
ing steel in the various processes of heating and 
cooling would be an almost impossible task, but to 
state the causes commonly experienced is a much 
simpler matter. 

In the shop having the ordinary furnace capacity 
it is considered advisable to purchase all tool steel 
in the annealed condition. While it is generally 
considered that the steel maker knows better how to 
anneal the product of his mill than the average 
man in a heat-treating plant, he cannot anticipate 
everybody's requirements. As a result mill annealed 



MISCELLANEOUS WORK. 323 

steel may or may not be in the best possible condi- 
tion for hardening. Then, again, a considerable 
proportion of the annealed steel purchased from a 
local steel warehouse is not annealed at the mill, 
but by some local concern equipped with suitable 
furnaces. The writer was at one time connected 
with a concern that regularly annealed about two 
tons of tool steel a day for local steel houses. We 
could not anticipate the uses to which the steel was 
to be put, as a result we attempted to get it as soft 
as possible without in any way injuring the metal. 

As previously stated softness is not the only 
requirement. There are many other things to be 
considered but some of these cannot be anticipated 
until one knows what is to be made from the steel. 
Strains cannot be successfully removed from steel 
unless it is blocked out somewhere near to the fin- 
ished shape. This is especially true of such tools as 
dies, milling cutters, gauges, etc. As a result, steel 
to be made into such tools should be carefully an- 
nealed after roughing out, even though it has been 
previously annealed. 

Steel that has been over annealed is in no condition 
for hardening, and should be re-annealed to remove 
strains and to refine the grain previous to the hard- 
ening heats. Many tools are ruined in the process 
of hardening, because the steel was not in condition 
to harden. 

As commercial bar steel has a decarbonized sur- 
face occasioned by the action of the oxygen in the 
air on the carbon in the surface of steel during the 
process of rolling and hammering in the steel mill, it 



324 FORGE-PRACTICE. 

is necessary to remove this exterior portion for a 
depth sufficient to get beneath the affected metal. 
The surfaces of forgings are decarbonized in the 
same way. In order to get good results when hard- 
ening an equal amount of surface stock should be 
removed from all parts of the piece so that there may 
not be left at any point metal that does not contain 
as much carbon as the balance of the piece or un- 
equal contraction or ununiformly hardened surfaces 
will result. It is always better to remove a trifle 
more surface stock than not quite enough. 

Pieces that are to be hardened should never be 
straightened when cold. If a piece of steel that is to 
be made into a tool is bent, heat it red hot, straighten, 
and then anneal. If steel is straightened when cold 
it is almost sure to return to its original form when 
heated for hardening. 

Overheating is a common cause of trouble. The 
steel is weakened because the interior structure is 
coarsened. Overheating also has a tendency to 
cause steel to crack in a direction corresponding to 
the axis of the piece. 

Ununiform heating of steel, when hardening, is 
the most common source of trouble experienced by 
the hardener, and manifests itself in cracks, or 
breaks, the direction of which corresponds to the line 
of ununiformity of temperature. 

Long-continued heating (soaking) renders steel 
weak, and should always be avoided. On the other 
hand heating should never be carried on more 
rapidly than is consistent with a uniform tempera- 
ture throughout the piece. 



MISCELLANEOUS WORK. 325 

Steel as it comes from the mill sometimes contains 
laps or seams. If either of these defects are noticed 
the steel should be returned to the party from whom 
it was purchased, as any tools made from such stock 
are almost sure to go to pieces when hardened. Such 
defects, however, are not common at the present 
time, as the inspection of ingots and bars is much 
more thorough than it was at one time. Such 
defects may be so located that they cannot be seen 
until the piece breaks. If the steel contained a seam 
its walls will generally have a much different appear- 
ance than the walls of a crack which took place in the 
bath. In the latter case they will be clean except 
for such stains as the contents of the bath may have 
caused. 

Piping is a defect not very often seen in com- 
mercial tool steel. When the ingot of steel is cooling 
in the mold the portion near the center remains 
fluid much longer than that near the walls of the 
mold, as a result the center portion contracts more 
than the balance, leaving a depression at the center 
at the top of the ingot. This defective portion is 
cut away (cropped). At times the defect extends 
into the ingot for a greater distance than the oper- 
ator is aware of, and, as a result, it is not all re- 
moved. When the ingot is heated for rolling the 
walls of these defective portions become oxidized 
and do not weld together, the defect extending 
through a number of bars. Ingots and bars are 
subjected to a very rigid inspection in all first-class 
mills and if "pipes" are discovered the bars are cut 
up and remelted. No reputable steel maker would 



326 FORGE-PRACTICE, 

knowingly allow a piped bar to get out of the mill, 
yet once in a while one will get by. When discovered 
such bars should be returned, as any tool made from 
them, unless the piped portion was cut away, is almost 
sure to go to pieces when hardened. The writer 
knows of a number of concerns using immense quan- 
tities of tool steel who have every bar that is to be 
made into costly tools inspected and tested before 
it is placed in the stock rack. This is done in a very 
systematic manner. A thin piece is cut from each 
end of the bar by means of a power saw and the sur- 
face is carefully inspected under a powerful micro- 
scope for imperfections. If none can be found the 
pieces are hardened and then broken as nearly as 
possible across the center. The fractured surfaces 
are then inspected under the microscope, if no 
defects appear one or more of the pieces are tested 
with a "Shore Scleroscope." If the steel shows up 
all right under the inspection and test the bar is 
marked O.K. and placed in the steel rack. 

At times a bar of steel will be found that shows 
disintegration of some element. This is caused by 
the particles of the element separating from the steel 
and pocketing at some point. It is almost impos- 
sible to detect this defect until the piece is machined, 
and even then, the removal of material may not 
uncover the pocket, and the piece may be finished 
and turned over to the hardener. In all probability 
it will go to pieces in the bath. If the bar from which 
a piece containing a defect of this kind can be located 
it should be condemned and returned to the party 
from whom it was purchased. Defects of this kind 



MISCELLANEOUS WORK. 327 

are rare, and for this reason but little understood 
by the men engaged in heat-treating steel. 

Hardened pieces, especially those that are round or 
oval in form, sometimes show soft spots on the sur- 
face. At one time it was considered by many hard- 
eners, and by a number of writers on the subject 
of hardening, to be almost, or quite impossible to 
avoid this trouble. At the present time it is con- 
sidered unnecessary to have such spots. They are 
caused by scale forming on the surface while the 
piece is being heated, and while most of the scale will 
"strike" (drop off) when the piece is placed in the 
bath small particles may remain on the piece and 
prevent, or retard hardening. This can be pre- 
vented by heating in a manner to prevent oxidation 
of the surface, and also by using a strong salt solu- 
tion in a bath of the description shown in Fig. 278. 
Another cause for soft spots is the pocketing of 
steam at certain points. The bath shown in Fig. 278 
will prevent the steam collecting at any portion and 
insure uniformly hardened surfaces. 

It is sometimes necessary to make a tool from a 
piece of i steel that is not of sufficient diameter for 
the purpose. In such case the steel is given the 
proper diameter by upsetting. If such practice is 
necessary select steel enough smaller than finished 
size so that the process of upsetting is very thorough. 
The upsetting should be accomplished by blows suf- 
ficiently heavy to reach to the center of the piece, or 
unsatisfactory results will follow when the piece is 
hardened. It is poor practice to upset a portion of a 
piece that is to be hardened allover, as the flow of 



328 FORGE-PRACTICE. 

the stock occasioned by the working of the bar in the 
mill will be in one direction, while that occasioned by 
the upsetting will be at right angles to the first, thus 
creating the worst possible condition for hardening. 
Unless all portions of a piece can be thoroughly 
upset it is unwise to attempt to increase its diameter. 
As a rule upsetting a piece of tool-steel that is to be 
hardened is not advisable; but, where it must be 
resorted to be sure that the precautions mentioned 
are closely observed. 

Pack Hardening. — The term Pack Hardening was 
applied to the superficial carburizing of tool steel 
surfaces about twenty-five years ago while the 
writer was in charge of a heat-treating department 
doing a large jobbing business. We were hardening 
a great many punch-press dies of unusual size and 
complex design, milling machine cutters, and various 
other tools. 

At that time there was a shortage of skilled help 
versed in the heat treatment of steel. The volume 
of business, and the requirements of the tools we 
were hardening forced us to experiment along lines 
that would enable us to successfully harden tools 
that were made from steels the make and compo- 
sition of which we were many times ignorant of. 

This was before the modern oil-hardening steels 
were made, or, at least, generally used. We rea- 
soned that as thin pieces of steel hardened in oil 
seldom cracked or warped to any extent, it would be 
advisable to treat ordinary tool steel tools so that 
they would satisfactorily harden in oil. As bone 
contains a considerable percentage of phosphorus 



MISCELLANEOUS WORK. 329 

and this element is highly injurious to steel, espe- 
cially steel made into cutting tools, we adopted 
leather as the carburizing agent. An experience of a 
quarter of a century has failed to convince me that 
any packing material that I have experimented with 
is better suited to this work than a good grade of 
charred leather. Although several satisfactory com- 
mercial carburizers have been analyzed and found to 
contain a high percentage of leather, none of these 
worked better than leather alone. 

Although this method is used very extensively in 
several large plants, its use is no where near as gen- 
eral as it should be, because if properly done breakage 
is almost entirely eliminated, and warping is reduced 
to the minimum. 

High-carbon as well as low-carbon steels respond 
to this treatment, although if the steel contains more 
than 1.25 per cent carbon, charred hoofs, or a mix- 
ture of charred hoofs and horns, should be used 
instead of leather. 

An argument sometimes advanced against this 
method is its high cost. When we consider that 
quite a number of tools can be packed in a box and a 
number of these boxes can be treated at a time it 
will be seen that the actual cost is in this way con- 
siderably lessened. Even though the cost were 
greater its use is to be advocated when we consider 
that dies treated by this method will last many 
times longer than those hardened by the ordinary 
fire and water method. Milling-machine cutters will 
be found to run considerably faster and stand up 
many times longer betw^een grindings. Taps and 



330 FORGE-PRACTICE. 

dies will wear much longer, and other classes of tools 
will show an increased efficiency overbalancing the 
extra cost of treating and is therefore to be advocated. 

There are several classes of tools that, under cer- 
tain conditions, do not prove as efficient when pack 
hardened. For instance, draw broaches doing ex- 
tremely heavy work in proportion to their diameter; 
slender piercing punches used on stock whose thick- 
ness exceeds the diameter of the punch and other 
tools that are slender in cross-section that are sub- 
jected to excessive tensile or crushing strains, but the 
classes of tools that do not satisfactorily respond to 
this treatment are few in comparison to those that 
are wonderfully helped by it. 

Temperature. — The temperature to be employed 
should be determined by test wires and pyrometer, 
and should rarely exceed the critical range of the 
steel which runs from 1375° to 1400° F. The length 
of time the pieces should be held at the red heat 
depends on the size and character of the piece. 
Before packing in the box each piece should be wired 
with iron binding wire for use in drawing from the 
box and dipping in the bath. Packing in the boxes 
is carried out the same as for case-hardening except 
that charred leather is used in place of the other 
carburizing materials. 

Time. — The length of time the pieces should be left 
in the box after reaching the critical temperature 
depends on the size and character of the tool. Small 
taps I" to I" should be left in the box one-half hour; 
those i" diameter two hours; reamers of the same 
size fifteen to thirty minutes longer; milling machine 



MISCELLANEOUS WORK. 33I 

cutters from two to four hours according to size and 
the use to which they are to be put; and punch- 
press dies from two to four hours according to thick- 
ness of the walls. Swaging dies are one of the most 
pronounced examples of the advantages of pack 
hardening. If they are to be subjected to very se- 
vere duty the heat employed should range from 30° 
to 50° higher than for milling cutters, that is, from 
1400° to 1430° F. This is to secure a deeper pene- 
tration and a more solid backing for the surface 
receiving the rough usage. Stay-bolt taps should 
be packed in a pipe, never in a box, as drawing the 
red-hot tap through the packing material in remov- 
ing it from the box would be sure to bend it. 

Gauges. — Pack hardening provides the most satis- 
factory method of hardening gauges of all kinds. 
It also makes possible the use of lower grades of 
steel than would be possible if the ordinary methods 
were employed. Ring gauges and other forms hav- 
ing holes passing through them, where the walls of 
the holes are to be subjected to wear, should be hard- 
ened in a bath having a jet of oil projected by a 
pump, the jet passing through the hole under con- 
siderable pressure forces all vapors away and allows 
the oil free access to the surfaces desired hard. If 
the outer portion of the gauge is irregular in form 
so that there is a heavier wall of steel at one side of 
the hole than the other, it is a good plan to encase 
it in fire clay, which may be wired on to prevent it 
from cracking, and breaking away. This should be 
done before the gauge is placed in the hardening box 
and may be removed after it is taken from the bath. 



332 



FORGE-PRACTICE. 



This, of course, leaves the outer walls soft, and 
applies only to pieces where the walls of the holes 
are the only portions desired hard. 

TABLE OF APPROXIMATE TEMPERATURES. 
Forging and Hardening Carbon Steel Tools. 



Approximate 
Carbon Content. 


Approximate 

Forging Tempera- 

ature. 


Critical 
Range. 


Approximate 

Hardening 
Temperature. 


0.60 per cent 


i6oo°-i8oo°F. 


1340 "-1380° F. 


1480° F. 


0.70 per cent 


1600 °-i 700° F. 


I340°-I375°F- 


1470° F. 


0.80 per cent 


1600 °-i 700° F. 


I340°-I365°F. 


1465° F- 


0.90 per cent 


i6oo°-i650°F. 


1340 "-1360° F. 


1460° F. 


1 . 00 per cent 


1600° F. 


1340 "-1360° F. 


I4.S0° F. 


I . ID per cent 


1550° F. 


1340 "-1360° F. 


1440° F. 


I . 20 per cent 


1500° F. 


1 340°-! 360° F. 


1425° F. 


I . 30 per cent 


1500° F. 


1 340°- 1 360° F. 


1410° F. 


I . 40 per cent 


1500° F. 


i340°-i36o°F. 


1400° F. 



Case Hardening. — In the process of case hardening, 
a hard surface is produced over a soft center, or core. 
The metals commonly treated are wrought iron, low- 
carbon steel, and cast iron. 

The process is a modification of the cementation 
process of converting wrought iron into blister steel 
and differs from it essentially in that it is not carried 
so far. In the cementation process the carbon is 
charged to the center of the iron, while in case 
hardening it is stopped when a case of hardening 
steel deep enough to answer the purpose is pro- 
duced. 

The proper selection of stock to use for articles 
that are to receive this treatment should be given a 
great deal more consideration than is generally the 
case. In practice, any low-carbon stock whose 



MISCELLANEOUS WORK. 333 

initial cost is low, and which machines easily, is 
many times selected without regard as to whether 
the core is strong enough to resist any strains it may 
receive. If a hard surface is the only consideration, 
a stock low in carbon is selected, usually one that 
does not contain more than 0.20 per cent. If 
bending, breaking or other strains are to be encoun- 
tered it is necessary to select one that contains a 
higher percentage. In some instances it is neces- 
sary, in order to obtain needed strength, to use steel 
containing 0.60, 0.80 or i per cent carbon. In case 
the high carbons are used it is advisable in most 
cases to avoid water baths in dipping, using instead, 
a bath of oil. In this way a very hard surface with 
a soft, strong core is obtained. 

Probably no one branch of hardening has received 
more intelligent study in the last twenty-five years 
than the one under consideration ; yet, in some shops, 
the subject is given no thought and, as a result, an 
inferior article is being turned out, which, if certain 
parts were properly case hardened, would be a satis- 
factory product. 

Quick Case Hardening. — It is necessary at times to 
case harden a few small screws, or other small articles, 
and depth of penetration is not a factor to be consid- 
ered. Under such circumstances the necessary hard- 
ness may be produced by heating the pieces to a red 
and applying a small amount of cyanide of potassium, 
re-heat the pieces to a red and plunge in clean, cold 
water. The depth of penetration may be increased 
by several applications of the cyanide, reheating 
after each application. Always make sure that the 



334 FORGE-PRACTICE. 

direct blast does not strike the pieces, as the resulting 
oxidation would decarbonize the surface and undo 
what is attempted. 

If colors are desired it will be necessary to polish 
the surfaces and have them free from grease of any 
kind. The pieces should be heated in a tube, or 
covered, when in the fire, with a piece of sheet iron 
to protect them from the direct action of the flame. 
They should rest, when heating, on a clean surface, 
usually a piece of fire brick or iron. The quality 
of the colored surfaces may be bettered by intro- 
ducing air into the water at the location of dipping. 
This may be accomplished by taking a piece of j" 
pipe and placing one end in the bath 3" or 4" below 
the surface, then blowing on upper end and passing 
the pieces through the air bubbles in the water. 

Yellow prussiate of potash was formerly used quite 
extensively in quick case hardening either alone, or 
in a mixture of 2 parts prussiate of potash, i part sal- 
ammoniac and I part salt. At the present time it is 
nearly impossible to get the potash. There are sev- 
eral quick case hardening compounds on the market. 
Some of these give very good satisfaction, most of 
them have this to their credit, they are not poison- 
ous, while cyanide of potassium is a violent poison 
and should be kept under lock and key when not 
in use. 

Carburizers. — To get good results when doing case 
hardening on a large scale one must understand the 
selection of stock from which articles are to be made, 
the effect of different carbonizing materials, and the 
effect of different temperatures on the stock. He 



MISCELLANEOUS WORK. 335 

must know what results are desired in the finished 
product and how to obtain these results. There are 
a number of carburizers used in charging carbon into 
iron and steel. Granulated raw bone is more com- 
monly used than any other material. It comes in 
several different sizes of granules. The coarser 
grades are used for long runs, while the finest is used 
for short exposures. Raw bone is rich in phosphorus, 
and as this causes brittleness when present in steel 
this form of bone should not be used for articles 
that are to be subjected to shock or blow unless they 
are of a form that insures the desired strength. 

Charred Bone. — Bone that is burned sufficiently to 
remove the phosphorus and grease may be procured 
commercially, or it may be charred in the hardening 
furnace by filling hardening boxes with raw bone, 
placing the covers in position and setting the boxes 
in the furnace at the end of the day when the fur- 
nace has been run for several hours. At the time of 
placing the boxes in the furnace the fire should be 
shut off. as there will be sufficient heat in the walls 
of the furnace to char the bone. However, should 
the walls of the furnace be light in construction and 
not hold the heat long enough to accomplish the 
desired result, the fire may be run very low for a 
time then shut off. The boxes may be left in until 
morning. When removed the material is ready for 
use. 

Animal Charcoal. — Thoroughly burned, specially 
treated bone known as animal charcoal may be pro- 
cured commercially and is used for the finer grades 
of work. Another form of burned bone, known as 



336 FORGE-PRACTICE. 

hydrocarbonated bone, is used for certain fine grades 
of work. This is animal charcoal treated with oils. 

Wood Charcoal. — Hard-wood charcoal is used as a 
carburizer either alone, or mixed in various propor- 
tions with other carbonizing materials and should be 
granulated before using. Granulated charcoal may 
be procured commercially, or it may be granulated 
and sorted to size by sifting. To do this econom- 
ically on a large scale special grinding and sifting 
machines should be used. Wood charcoal is not a 
satisfactory packing material when the work is to 
run for a long period. 

Leather. — Charred leather provides the very best 
material for use on the finer grades of work. As it 
is more expensive than bone it is not used when bone 
will answer the purpose. It may be procured com- 
mercially but should never be bought from any but 
dealers whose reliability is known, as there is a ten- 
dency on the part of some to use any scrap leather 
they can get. 

Leather may be charred in the shop by getting the 
scraps that soles and heels of shoes are punched from 
as this gives a heavy scrap. Old belting that has 
passed its usefulness is also used. The leather should 
be cut in 3" or 4" pieces and packed in the box as 
was explained under Charring Bone. Care should 
be exercised, or the leather will be charred too much. 
This process should be carried on only long enough 
to char the leather until it can be crushed in the hand. 

Barium Carbonate. — A mixture of 3 5 parts barium 
carbonate and 65 parts granulated wood charcoal 
is used with excellent results in a number of shops. 



MISCELLANEOUS WORK. 337 

The proportions given need not be accurately ob- 
served but may be varied to meet requirements. 

Mixtures. — Various mixtures of carbonaceous ma- 
terials are used in packing work. Materials that 
have no direct action on the steel are many times 
used with the direct-acting cements. Two parts 
common salt added to 8 parts granulated hard-wood 
charcoal materially increases the action of the latter, 
or the salt may be added to mixtures containing char- 
coal, with good results. 

Mixtures for Short Runs. — Where pieces are not 
to be run for a great length of time the following 
mixtures may be used: i. Granulated hard-wood 
charcoal, 6 parts; lamp black, ?. parts; granulated 
charred leather, 2 parts. The charcoal and leather 
should be ground fine or the lamp black will settle 
to the bottom of the mass. 2. Finely granulated 
raw bone, 7 parts; animal charcoal, 2 parts; pow- 
dered charred leather, i part. 3. Powdered wood 
charcoal, 4 parts; sawdust, 5 parts; salt, i part. 
4. Hydrocarbonated bone, i part; charred leather, 
4 parts; charcoal, 4 parts; salt, i part. 

The formulas for dozens of mixtures could be given 
but a study of the effects of the various ingredients 
used will enable one to adapt the quantities, and 
select the carburizers to meet the various require- 
ments. It should be borne in mind that raw bone 
should not be used where extreme toughness is 
necessary, and that leather is a safe carburizer for 
all steel containing less than 1.25 per cent carbon. 

The Boxes. — Articles to be case hardened are 
packed in boxes or tubes completely surrounding 



338 



FORGE-PRACTICE. 



each piece with the carbonizing material. Small 
pieces and those that are long and slender, especially 
the latter, should be packed in tubes as more uniform 
temperatures can be obtained, and there is always 
danger of springing long slender pieces when drawing 
them through the packing material in a box when they 
are red hot. As such pieces must be dipped vertically 
in the bath they canot be dumped into the bath, 
but must be handled individually. The tubes may 
be pieces of iron pipe having one end closed tightly 
by means of a cap, or a plug may be driven in and 
securely pinned in place. When the tube is filled. 



1 



FiG. 322. 



the opposite end may be closed by a loosely fitting 
plug which sets below the end of the tube, giving 
room for the fire clay used in sealing (luting) as 
shown in Fig. 322. 

Boxes of various sizes and shapes, made from one 
of a number of materials may be used. Those to be 
used for small work should themselves be small in 
order that the pieces near the center may be heated 
to a red nearly as soon as those nearer the walls. 
Boxes that are larger in size give best results if rect- 
angular in form. At times the shape of the piece 
necessitates the use of a square box. Round boxes 
work well for small pieces but are not so easily 



MISCELLANEOUS WORK. 



339 



handled as other forms; small, round boxes, however, 
are very desirable at times. 

The box used more than any other is rectangular in 
form and has ribs at its upper edge as shown in Fig. 
323. These not only provide a means of handling 





Fig. 323. 




t: cr 

Design of Case Hardening Box Used in some Plants. 



with the grappling iron, or dumping fork, as it is 
many times called, but tends to keep the boxes from 
warping. Round boxes are generally handled with 
special tongs made to fit the box. 

The material used in making boxes may be sheet 



340 FORGE-PRACTICE. 

iron, low-carbon sheet steel, malleable cast iron, or 
gray cast iron. Boxes made from sheet iron and 
sheet steel will last much longer than those made 
from the other materials mentioned, while malleable 
iron is more durable than gray iron. The number of 
gray cast-iron boxes in use in hardening plants prob- 
ably exceeds all the others, as they are more cheaply 
and readily obtained. However, where very high 
heats are to be used, cast iron is relatively short lived. 

Time. — The length of time any article should be 
exposed to the carburizing effects of the material 
in which it is packed depends on the depth of pene- 
tration desired. It should be borne in mind that 
iron and steel do not commence to absorb carbon 
until nearly, or quite red hot. Many authorities 
claim that carbon penetrates iron at the rate of |" 
in twenty-four hours and that this rate is fairly 
constant. The character of the metal being charged, 
and the temperature to which it is raised has consid- 
erable to do with the rate of penetration, but as a 
basis on which to calculate time of exposure, it is 
safe to consider the rate mentioned, making due 
allowance for conditions. 

Small Pieces. — When packing small pieces for car- 
burizing it is advisable to use small boxes. First, 
place a layer of packing material i" or i\" deep in 
the bottom, on this a layer of work, making sure that 
they are i" from the walls of the box and \" to |" 
from one another, on this spread a layer of packing 
material, then one of work and so continue until the 
box is filled to within i\" of the top. After each 
layer of packing material is laid, tamp lightly with a 



MISCELLANEOUS WORK. 34 1 

block of wood. There should be a layer of packing 
material at least i" thick between the top layer of 
work and the cover. After placing the cover in 
position, seal the space between it and the box with 
fire clay mixed with water to the consistency of 
dough. This sealing, or luting, as it is many times 
called, should be allowed to dry before placing in a 
furnace. 

The cover should have five or six \" holes drilled 
near the center. After placing in position y^" wires 
should be run through these to the bottom of the box. 
These wires should project i" above the top, and 
should be sealed with fire clay to prevent the escape 
of gas. These are known as test wires and are used 
to determine when the contents of the box are red 
hot to the center. 

Marking Boxes. — Where boxes of work requiring 
different time exposures are to be heated in a fur- 
nace, it is necessary to mark the boxes so that they 
can be easily distinguished. This may be done by 
numbering each box with common white marking 
crayon. These marks can be easily seen when the 
boxes are red hot. The boxes requiring the longer 
exposures should be placed at the back of the fur- 
nace. 

Testing. — When, in the judgment of the furnace- 
man, a box has been exposed long enough to be 
heated to a red, one of the test wires should be drawn 
by means of long tongs and examined. If it is red, 
the time should be noted and recorded on a tally 
sheet, or slate, together with the number of the box, 
what it contains, time it should be removed from the 



342 



FORGE-PRACTICE. 



furnace, highest temperature it received and any 
other facts those in charge think best to keep. 
Below is a sample tally sheet : 





Contents. 


Furnace K 


0. I. Date, May 6, 1918. 


Box No. 


Red Hot. 


Remove. 


Highest 
Pyrometer 
Reading. 


I 
2 

3 
4 


Links 

Binders 

Binders 

Bolts 


10.10 10.45 

10.25 11-25 

10.30 11.30 
10.50 2.50 

Furnace Operator, 


1450 
1450 
1455 
1470 

John Smilh. 



The above is an abbreviation of a form of tally sheet 
used in several factories. It may be varied to meet 
requirements. There are a number of advantages 
derived from the use of a standard tally sheet. 
They enable those in charge to keep closely in touch 
with the treatment each box receives. If the 
results show that the pieces were not given the proper 
temperature or time exposure, note may be made of 
the fact, and the practice varied with the next batch. 
It obviates difficulties that arise when the oper- 
ator's memory is relied on as to what is in a given 
box, when it should be removed from the furnace, 
and also tends to cultivate carefulness on the part 
of the operator. 

The man in charge of the heat-treating depart- 
ment should be able to differentiate between work 
not requiring much care, and that requiring the 
utmost care and attention. For instance, a batch 
of ordinary machine nuts and several long, slender 
shafts, or spindles may be received at the same time. 



MISCELLANEOUS WORK. 343 

The nuts may be packed in raw bone and run at 
fairly high heats, while the spindles should be 
packed in tubes with charred bone, leather, or some 
mixture that will not give off phosphorus, run at a 
low temperature, and will probably require a def- 
inite time exposure. 

The Quenching Bath. — The design and contents 
of the hardening bath do not receive the attention 
they should in some shops. A batch of work may 
be packed all right, receive the proper time exposure 
and temperature and yet not give desired results, 
because the quenching bath was not deep enough, 
or had no means of separating the pieces from one 
another, or the liquid was not what it should have 
been. When the character of the work is such that 
a barrel of water that is provided with no means of 
agitation will produce desired results, it is folly to 
go to the expense of rigging up an expensive bath, 
but when such a bath is necessary to get definite 
conditions, it is worse than folly not to provide it. 
The tank should be deep enough so that the pieces 
will cool below a red before they reach the bottom, 
if the box of work is dumped. Where the pieces 
are taken singly from the box and worked around in 
the bath until cold a very deep bath is not necessary. 
Large, heavy work is seldom dumped. 

Tank with Separating Wires.— In cases where the 
work is dumped directly into the bath from the box 
it is well to provide some means of separating the 
pieces or ununiform results will follow. To effect 
this, wires may be provided as shown in Fig. 279, 
making sure that no two consecutive rows of wires 



344 rORGE-PRACTICE. 

are directly in line. By this arrangement the work 
is not only separated but is turned over and over as 
it bounds from one wire to another and descends. 
The bottom of the tray (a) should be of wire netting 
or thoroughly perforated sheet metal in order that 
the water may circulate freely about the work, and 
should be in the form of a tray. It should be pro- 
vided with handles to facilitate its removal. Directly 
under this should be a pan {b) also provided with 
handles to receive the packing materials. 

If bone is the carburizer used, it may be removed 
from the pan and dried on top of the furnace, or in 
some convenient way and used for work such as 
screws, etc., that do not require a strong material. 
For certain classes of work it may be used in con- 
nection with fresh bone, in proportions varying 
according to the requirements of the pieces. 

This bath should be provided with a supply pipe 
as shown, and also with an overflow pipe. It is well 
to arrange a hood over most baths where work is 
dumped. This hood should have a pipe running 
into a chimney, or into the atmosphere to conduct 
the steam, smoke, sparks, etc., away, as they are 
extremely annoying and tend to injure the eyesight 
and health of the workmen. 

While shafts, spindles, small axles and similar 
pieces are many times dipped one at a time ver- 
tically, excellent results, in many instances, follow 
the use of a bath of the form shown in Fig. 280 where 
inclined shelves are provided to allow the pieces 
to go down into the bath with a rolling motion. 
These shelves should be thoroughly perforated to 



MISCELLANEOUS WORK. 



345 



allow the liquid constant contact with the steel. 
This is a modification of the so-called "Coffin" 
method of treating car axles and, as a rule, pro- 
duces good results. 

The bath shown in Fig. 278 having perforated pipes 
up the sides, is adapted to work that is to be dipped 
rather than dumped. For certain kinds of work a 




bath having pipes coming in from the sides and one 
or more from the bottom is desirable. In fact, when 
the work is done in quantities that warrant it, the 
bath should be designed to give the best possible 
results with the pieces being hardened. 

Fig. 324 shows a bath designed for colorcase hard- 
ening which has an air pipe entering the water- 



346 FORGE-PRACTICE. 

supply pipe. A bath of this description should be 
in every plant where color work is done. 

Oil Baths. — Where oil is the quenching medium 
employed, some means should be provided for cool- 
ing it, because, unless used in large bodies it becomes 
heated quickly and uniform results cannot be ob- 
tained as some pieces will enter the bath while the 
oil is cold and the balance will enter while it is at 
various temperatures. As extremely cold oil seldom 
works well, care should be taken in planning for the 
cooling coils. In a bath of this kind the oil is 
usually taken from the top and pumped through the 
coils as shown in Fig. 277 and returned to the tank 
at any desired part. For certain work the supply 
should enter at the bottom ; for other work the inlet 
should be at one or more sides, or pipes may be pro- 
vided to enter at a number of places and furnished 
with valves so that the entry may be where it will 
work best for the individual job. 

For a number of reasons the contents of the hard- 
ening box should never be dumped directly into the 
oil. If the pieces are large, or of intricate design, 
they should be removed from the box individually 
and immersed in the bath by means of tongs, a hook, 
or wire and worked around until cooled considerably 
below a red when they may be lowered to the bottom 
and allowed to remain until cold. If they can be 
hardened all right by dumping, the bath should be 
provided with an inclined wire cloth dumping screen 
as shown in Fig. 325 onto which the contents of the 
box should be dumped. The packing material will 
pass through the screen into the iron pan below 



MISCELLANEOUS WORK. 



347 



while the work will roll down the incline into the oil. 
The packing material, if dumped into the oil, will 
set it afire, and also dirty the oil, rendering it useless. 
Some hardeners always use this dumping screen even 
when quenching in water. 

Examples of Case Hardening. — Sinall Screws. — 
As the stock used in making machine screws varies, 
it is necessary to vary the treatment at times. If 
they are made from Bessemer screw wire, bone that 
has been used once for short runs gives better results 




Fig. 325. 



than raw bone, especially on small slotted screws. If 
no partially expended bone is available, it is advisable 
to char some as raw bone will phosphorize the screws 
and make them extremely brittle and no amount 
of tempering will remove this brittleness. Screws 
larger than f " do not show the effects of brittleness 
as much as the smaller sizes as there is a large, soft 
core that is not affected. 

Nuts. — Machine nuts, if small, and a deep pene- 
tration is not necessary, may be packed in small 
boxes with equal parts of charcoal and raw bone and 



34^5 PORGE-PRACTICE. 

run from three to five hours according to size and 
depth of hardness desired. If the nuts are to be 
polished after hardening a Httle longer exposure will 
be necessary. Nuts |" and larger may be packed 
in raw bone and charcoal of equal parts, run from 
five to seven hours and dumped into the bath. If 
colors are desired, the fiats and tops of the nuts must 
be polished and the packing material should be some 
mixture especially suited to the work. For general 
purposes the following works well. Eight parts 
No. I charred bone, 2 parts animal charcoal, and i 
part charred leather. Excellent results follow the 
use of the bath shown in Fig. 324 where a quantity 
of air is introduced into the bath. If brilliantly col- 
ored surfaces are desired, mix a small amount of pow- 
dered cyanide of potassium with the packing mix- 
ture. As previously stated, all work that is to be 
colored must be absolutely clean and free from all 
grease. In some hardening plants every operator 
packing work of this character wears gloves to pre- 
vent the moisture of the hands getting on the work. 
It is advisable to observe this precaution if good 
results are desired. 

All case hardened work should be thoroughly 
washed in hot soda water, then in boiling water and 
then thoroughly dried. Colored work should be 
oiled. All this should be done immediately on 
removing from the quenching bath. 

Deep Penetration. — Where very deep penetration 
is desired, it is necessary to expose the work to the 
influence of the carbonizing material for a long 
period. The writer has in mind some nuts that were 



MISCELLANEOUS WORK. 



349 



about 1 6" across flats. Instructions called for a 
depth of carbon penetration of at least |-". They 
also stated that the walls of the holes and the stock 
immediately around the holes must be soft as the 
nuts were to be threaded after hardening, and that 
the flats and tops must be nicely colored. Test 
pieces of steel made from the same billet as the nuts, 
came with them. These were to be treated the same 
as the nuts, and broken to determine the depth of 
carbon penetration. 




On account of their size it was considered advisa- 
ble to pack but one nut and its test piece in a box. 
The packing material used was the coarser grades of 
raw bone. Before packing, a round plate of cast 
iron ^" diameter larger than the hole, was pro- 
vided to cover each end of the hole, as shown in Fig. 
326. These were provided to prevent the carbon gas 
acting on the walls of the hole. The plates were 
bolted in place and an eye bolt provided for use in 
handling. Three re" vent holes were drilled in each 
upper plate; these were covered with fire clay. 



35© FORGE-PRACTICE. 

While carbon will penetrate iron and steel when in 
contact with carbonaceous materials, it is a known 
fact that the material gives off all of its available 
carbon in a few hours ; the length of time depending 
on the size of the kernels. In the case of the nuts, 
it was considered best to run them fifteen hours, let 
them cool off, repack in fresh material and run for an 
equal length of time, making thirty hours that they 
were exposed to carburization, at a temperature 
of 1700° F. They were packed again in a mixture 
of charred bone 4 parts, charred leather i part and 
exposed to a temperature of 1450° F. for four hours 
after they were red hot. 

Dipping the nut in the bath was a comparatively 
simple matter as the plant was equipped with a 
small crane. The crane hook was passed through 
the eye bolt and the nut dipped in a large bath having 
six delivery pipes from the sides, one from the bottom 
and one from the top. The results were all that was 
expected as the penetration was over |" and the sur- 
faces were nicely colored. 

At times, the ingenuity of the hardener is taxed 
to the limit. Results that are, apparently, beyond 
the range of human possibility are demanded and no 
method for producing these results is advanced. 
I have in mind an instance where the man in charge 
of a heat-treating plant was told that certain pieces 
being case hardened must show an increase of 25 
per cent in breaking strength, and, at the same time, 
show the same hardness test as formerly. He accom- 
plished the desired result by dropping his charging 
heat 50° F. and quenching in water heated to about 



MISCELLANEOUS WORK. 351 

115° F. The bath was supplied wdth water from an 
artesian well. Several pipes carrying live steam 
entered the supply pipe, each pipe being provided 
with a valve making it possible to get a range of 
temperature from about 50° F. to 150° F. He might 
have attained the desired strerigth by quenching in 
oil, but as the pieces had but a short time exposure 
to the carburizer they would not show the necessary 
hardness when tested. 

Local Case Hardening. — This term is applied to 
the practice of hardening one or more portions of a 
piece leaving the balance soft, and is accomplished 
by a number of methods. One method consists in 
charging carbon into a piece of work then cutting 
away the carbonized surface where hardness is not 
desired. Another method is to protect, by some 
means, the portions desired soft, so that the carbon 
will not penetrate. A third method consists in 
charging carbon into all surfaces, then protecting 
the portion desired soft by means of holders, or 
special tongs. As an example of the first method we 
will consider the block shown in Fig. 327 where the 
projecting ring (a) is the only portion desired hard. 
The block was rough machined, the ring was ma- 
chined to within grinding size on top and to within 
-^" of finish dimension for thickness and ^" depth. 

When packed for carburizing a thoroughly ex- 
pended bone was placed in the box to a depth of 2" 
and on this the block was placed with the ring upper- 
most. The hole was filled with expended bone, and 
the same material was placed around the block to 
within \" of the top. Raw bone of medium size 



352 



FORGE-PRACTICE. 



granules, mixed with an equal amount of wood 
charcoal, was then put in, covering the ring to a 
depth of i". The balance of space was filled with 
expended bone. The block was then subjected to a 
temperature of 1750° F. for eight hours after it was 
red hot. The box was then removed from the fur- 




FiG. 327. 



nace and allowed to cool. After cooling the block 
was machined to finish dimensions, then reheated 
to 1480° F. in a box with no packing material, except 
that the ring was covered on top and sides with dry 
fire clay, to a thickness of |" to prevent oxidation of 
the surfaces. 



MISCELLANEOUS WORK. 



353 



When the piece was uniformly heated to the tem- 
perature mentioned (1480° F.) it was placed on a 
specially prepared holder and a large stream of 
water projected against either end, as shown in Fig. 
283. The purpose of the stream against the bottom 
of the block was to cause, so far as possible uniform 
contraction of the piece. It had been found, by 
experience, that satisfactory results were not ob- 
tained by immersing in a tank as the vapors formed 
did not allow the water free access to the ring. 
In the open air with a large, strong jet of water these 
vapors were easily taken care of. 

By the second method mentioned, the portions 
desired soft are protected from the action of the 
carbon gas by covering with sheet iron or steel. 
These covers may be wired in position. Or the 
portions may be covered with wet fire clay, wound 
with wire to prevent its 
cracking away or a mixture 
of fire clay and asbestos 
may be used. Where local 
case hardening is done in 
large batches special cast- 
iron covers are made to 
protect certain portions 
desired soft. Or the por- /rH~' 
tions may be plated with \Lh_. 
either nickel or copper, this Fig. 32s. 

is costly and seldom re- 
sorted to where any of the other methods will answer. 

As an example of the third method we will con- 
sider the piece shown in Fig. 328 where a pair of tongs 



:20 



354 FORGE-PRACTICE, 

is used to protect the portion desired soft from the 
action of the bath. Under certain conditions it 
may be advisable to cool the ends in water until the 
red has disappeared, then to remove them from the 
water bath and drop the piece from the tongs into a 
bath of oil. This will stiffen and toughen the center 
portion without actually hardening it. Special 
holders are many times used instead of tongs. 

Fine Grain. — The process of case hardening, as 
ordinarily practiced, tends to produce a coarse grain 
in the carbonized portion. For many purposes this 
does not injure the product. As the size of the grain 
is directly proportional to the temperature given the 
steel, extremely coarse texture may be avoided by 
employing low heats in charging. In many cases 
this is objectionable on account of the time necessary 
to secure a desired penetration, as carbon pene- 
trates faster at high heats. To secure rapid pene- 
tration and yet get a compact grain two heats are 
many times employed. This is a modification of the 
Harveyizing process, and consists in packing the 
pieces for carburizing in the usual manner and 
running at a temperature of 1750° F. to 1850° F, 
for a length of time necessary to give desired pene- 
tration, then allow the pieces to cool, and reheat 
and harden as though they were of tool steel, except 
that slightly higher temperatures are employed 
(about 1475° F,) than for high-carbon tool steels. 

Under some conditions two quenchings are made, 
the first at a high temperature 1650° to 1750° F,, 
and then a second at 1400° to 1450° F. Unless this 
method is necessary to produce desired results its use 



MISCELLANEOUS WORK. 355 

is not to be advocated on account of the expense 
involved. The writer does not wish to be under- 
stood as advocating the exact temperatures men- 
tioned, as they must be adapted to the materials 
used, the design of the piece, and the use to which it 
is to be put. 

As modern manufacturing conditions demand a 
higher grade of case-hardened product than was 
formerly the case, dumping into the bath directly 
from the charging heat is not practiced to as great 
an extent as it was at one time. In some shops a 
very large proportion of case-hardened work is 
given two heats, i.e., the first for charging and the 
second for hardening. This practice is especially 
desirable where a pronounced line of demarkation, 
at the point where the hardened portion joins the. 
soft core, is objectionable. 

The depth of penetration of carbon should be no 
greater than is necessary to produce desired results. 
It is folly to run work, in the process of carburizing, 
for eight hours, when an exposure of five hours will 
give a penetration sufficiently deep. 

Under some conditions it is necessary to draw the 
temper after case hardening, this practice is resorted 
to where it is necessary to use a comparatively high- 
carbon steel in order to get a strong core. 

Case Hardening Brazed Articles. — At times it is 
desirable to case harden articles that have been 
brazed. Where possible such pieces should be 
brazed with a fairly high-temperature spelter, but 
the hardener seldom has anything to say about 
what shall be done to articles before they reach his 



356 FORGE-PRACTICE. 

department. For this reason it is advisable to heat 
one of the pieces in an open fire and see if the brazing 
starts at a full red heat, if it does not it is safe- to 
pack the pieces in a box with a desirable carburizer 
and run at a low red heat, making sure that this tem- 
perature is not exceeded at any time, and proceed 
as in any ordinary case hardening. When quench- 
ing work of this kind it is not advisable, generally 
speaking, to dump. The pieces should be quenched 
singly in such a manner as not to bring any strain 
on the brazed joint. 

The writer has case hardened many thousand 
pieces of brazed work. In some cases the object 
sought was a hard surface ; in others it was to stiffen 
the stock so it would stand a high torsional, or other 
strain. 

Carburizing with Gas. — There have been many 
changes and advances made during the past twenty- 
five years in the process of case hardening, none of 
which are of more importance to the manufacturer 
who finds it necessary to produce a deep penetration 
of carbon than the method of carbonizing with gas. 

Armor-plate manufacturers were handicapped 
when treating the plates by means of solid carbon- 
izers, and experimented with, and perfected, a process 
whereby the carbonizing could be accomplished by 
means of carbonaceous gas. The success of this 
method has led manufacturers of heating furnaces 
to place on the market muffle furnaces using gas as a 
carburizer. By this method more uniform results 
are obtained, especially where deep penetration is 
desired, than by the use of solid carbons. As the 



MISCELLANEOUS WORK. 



357 



gas can be constantly fed to the heated pieces any- 
desired depth of penetrations can be obtained without 
the bother and expense of repacking. A gas car- 
bonizing machine is shown in Fig. 329. 




Fig. 329. 

Baths of Cyanide of Potassium. — Gun frames, 
parts of apparatus and seme forms of tools where 
highly colored surfaces are desired, are case hardened 
by heating in a crucible of red-hot cyanide of potas- 
sium and then dipping in cold water. As in all 
methods of producing color work the surfaces must 
be nicely polished and absolutely clean before case 
hardening. 



$$8 FORGE-PRACTICE. 

The work must be suspended in the crucible in 
such manner that it is entirely submerged in the 
cyanide and so it does not touch the crucible at any 
point. This is usually accomplished by means of 
hooks suspended from rods placed across the top of 
crucible. 

For most small work a Cyanide Hardening Fur- 
nace of the type shown in Fig. 330 answers very well. 
Where the pieces are of a size and form that does not 
make possible the use of one of the commercial types, 
a furnace and crucible designed to meet the require- 
ments can be built. Cast-iron crucibles work nicely 
in heating cyanide as the temperatures employed are 
never extremely high when producing colors. The 
exact temperature depends on the character of the 
work, generally from 1375° to 1450° F. 

The pieces should be left in the cyanide until 
uniformly heated, and as much longer as is necessary 
to produce the desired depth of penetration. If 
colored surfaces with slight penetration is desired 
the pieces should be removed and quenched when 
uniformly heated to the proper temperature. 

Any form of moisture must not be allowed to enter 
the crucible as the resulting steam would cause par- 
ticles of the melted cyanide to fly, these produce 
painful burns which, on account of the poisonous 
nature of the chemical, are slow in healing. For 
this reason the operator should always wear goggles 
to protect the eyes and long gloves to cover the hands 
and arms. 

Hooks and tongs should be dried after use in 
quenching before using again. For this reason - a 



MISCELLANEOUS WORK. 



359 



plentiful supply of hooks, and several pairs of tongs 
must be provided. Furnaces are sometimes de- 
signed with a drying chamber so located that the 




Fig. 330. 



operator can place the hooks and tongs in it, and 
remove them without loss of time. 

Articles made from tool steel, and other high- 
carbon steels, are many times hardened by this 



360 



FORGE-PRACTICE. 




method in order to get the brilhantly colored sur- 
faces. In case the resulting hardness is too great 
the temper may be drawn the desired amount by 
means of an oil- tempering furnace without injuring 
the colors ; provided the pieces are allowed to remain 
in the oil until cooled below 400° F. 

As a rule extremely cold quenching baths produce 
more brilliantly colored surfaces than those whose 
^^^ temperature is above 

50° F. For this reason 
it is customary in some 
hardening plants to 
keep ice in the tank 
in warm weather un- 
less the water is from 
an artesian well or 
some supply that in- 
sures the desired temp- 
erature. 

If the fine vine-like 
bluish lines sometimes 
observed on high-grade 
case-hardened work are 
desired they may be 
produced by using a 
bath of the design shown in Fig. 331. The ends 
of supply pipes which are located above the tank are 
so constructed that the water comes from them in 
the form of spray. The heated pieces are passed 
through this spray then into the bath where they 
are worked around in the water until cool. 

Many forms of dies, especially those having 






I' I 



2h 



Fig. 331. 



MISCELLANEOUS WORK. 36 1 

engraving on the working faces, molds used in form- 
ing various substances to shape and numerous other 
articles are heated in red-hot cyanide for hardening; 
but in such cases colors are not sought. Molten 
cyanide provides an excellent means of heating pieces 
that must be free from oxidation, and which would 
not prove satisfactory if heated in lead. 

Melted cyanide gives off poisonous fumes which 
are harmful if inhaled. Furnaces used for the pur- 
pose under consideration should be provided with 
some means of getting rid of these fumes, the one 
shown in Fig. 330 has a pipe connected with the 
chimney. 

HIGH SPEED STEEL 

Forging High-Speed Steel. — For tools to be used 
in taking medium and light cuts, tool bits for use in 
tool holders are advocated as they answer every 
purpose and are much cheaper than forged tools. 
The desired shape can be produced by grinding, one 
holder answering for the various forms of tools used 
on a machine. This applies, of course, to tools used 
on lathes, planers, etc., particularly the former. 

In the case of milling cutters, blanks can be pro- 
cured of a size that allows for the necessary machin- 
ing. Punches are best made from bar stock even 
where considerable turning or other machining is 
necessary as such pieces, especially if round in form, 
are liable to burst from forging strains of a nature 
that cannot be removed by annealing. 

At the present time there is comparatively little 



362 FORGE-PRACTICE. 

trouble experienced when forging the ordinary forms 
of lathe tools. Smiths have become familiar with 
the higher temperature necessary for high-speed 
steel than is employed for carbon and the ordinary 
alloy steels. To get satisfactory results it is abso- 
lutely necessary that the steel be uniformly heated 
throughout. If the interior is hotter than the outer 
portion, cracks will develop near the center from 
uneven contraction when cooling. These defects 
are not easily detected as the exterior may be per- 
fectly sound. If the exterior is much hotter than 
the interior surface checks will result. High-speed 
steel should not be hammered when it is below a 
full red heat, the temperature range recommended 
by several manufacturers is 1650° to 1850° F., 
although in no case should it be hammered when it 
gives a metallic ring. The objection to high heats 
is that tools so treated do not stand up as well. 
Most steel makers furnish general directions for 
forging and hardening which are many times given 
in colors and it is rather difficult to determine just 
what is meant, because one authority's understanding 
of the temperature corresponding to a certain color 
is liable to differ materially from that expressed by 
another. For this reason, the smith when possible 
should ascertain by experiment the temperature 
that gives the best results with the steel he is using 
and the tools he is forging. A heat that may insure 
ease in forging may not put the tool in the best con- 
dition possible for producing the greatest amount of 
work in a given time. The smith should always 
bear in mind the fact that his office is not to produce 



MISCELLANEOUS WORK. 363 

the greatest number of tools in a given time, but 
rather to produce tools that will turn out the max- 
imum amount of woik in a given time. Unfor- 
tunately, it is the custom in some estabhshments to 
judge a smith's ability by the number of passable 
tools he turns out rather than by the amount of work 
these tools produce in a given time. 

Form of Tools. — The form of a tool must depend 
on the character of the work and the condition of the 
metal it is to be used on. If a tool is to be used on 
work requiring coarse feeds it must be given an angle 
of inclination with the cut that will insure sufficient 
clearance below the cutting edge so that the work 
will not rub on the tool below the cutting edge; this 
amount of clearance would not be absolutely neces- 
sary if fine feeds were to be employed. If the exact 
amount of feed is not known it is best to give suffi- 
cient inclination so that the tool will answer in any 
case. 

The writer's attention was at one time called to 
several tools that "fell dow^n" in a competitive test. 
The concern handling the steel was not satisfied with 
the results of the test and ordered an investigation. 
An examination of the tools showed that there was 
very little angle on the side of the tool as shown in 
Fig. 332, and as coarse feeds were employed in the 
tests it was impossible for the tools to cut. They 
were heated and bent to a greater angle as shown in 
Fig. 333. In the second test they stood No. i instead 
of being at the bottom of the list. An intelHgent 
study of tool angles is just as essential for the smith 
as a study of temperatures. 



364 



FORGE-PRACTICE. 



As a rule tools to be held in tool posts should be 
made from annealed stock and as this can be pur- 
chased at prices less than that of unannealed stock 
plus the cost of annealing in the average shop it is 
not wise to attempt the annealing of bars in shops 
having the ordinary furnace equipment. If the 
stock is bought in the unannealed condition it must 
be heated to cut to length. 





Fig. 332. 



•t^iG. 333- 



Annealing. — High-speed steel can be annealed so 
it is nearly as soft as carbon-tool steel. To accom- 
plish this, however, the proper facilities must be at 
hand and the steel must be slowly heated to the 
proper temperature and allowed to remain at this 
temperature for a time that insures an absolutely 
uniform heat, then cooled very slowly. Long con- 
tinued soaking should be avoided as it is apt to" pro- 
duce a coarse grain and set up strains that are liable 
to cause the steel to crack when hardened. The steel 
may be annealed in the bars by packing in iron pipes 
having one end tightly closed by means of a cap or 
plug. The pipe should be somewhat longer than the 



MISCELLANEOUS WORK. 365 

bars in order that the open end may be closed with a 
loosely fitting plug and securely sealed with fire clay. 
Several small holes should be drilled through this 
plug to allow gas to escape or the clay lutting will 
be blown away. The bars when in the pipe should 
be surrounded with green coal dust, powdered char- 
coal, powdered coke or some substance that will 
give off a gas that prevents oxidation of the surface. 
The pipes when packed may be placed in the fur- 
nace and gradually brought up to low red (1400° to 
1450° F.). The steel should be uniformly heated 
and should not be soaked in the fire, as long-continued 
heats produce a coarse structure and tend to increase 
the liability to rupture when the steel is hardened. 

When the bars are uniformly heated to the tem- 
perature mentioned the heat may be shut off and the 
whole allowed to cool. Any openings in the furnace 
should be closed as cold air, if it enters the furnace, 
chills the steel and retards the annealing operation. 

Box Annealing. — When annealing forgings, tool 
blanks, etc., it is advisable to pack in boxes of con- 
venient size using as packing materials powdered 
charcoal, coal, coke, or something that gives off a 
non-oxidizing gas. However, some parties claim 
good results from the use of asbestos, ashes, lime or 
sand. The writer has had good results from the use 
of finely powdered dry fire clay. A space of i|" 
should be left between the top of the packed work 
and the cover which should be filled with the packing 
material. The cover, which has three or four small 
holes drilled at the center to allow gas to escape, 
should be placed in position and sealed. 



366 



FORGE-PRACTICE. 



When a box of the description shown in Fig. 334 is 
used seaHng with wet fire clay is not necessary. The 
groove is quite a Httle wider than the cover flange, 
this allows a packing of finely sifted ashes, or dry 
powdered fire clay between the flange and walls of 
groove thus preventing air entering the box. The 
interior of the box may be lined with flre brick if this 
seems advisable. As a rule, however, a cast-iron 




Fig. 334. 




Dumping Fork for Fig. 334. 



box with reasonably thick walls and no lining will 
be found satisfactory. 

If possible the boxes should be placed in the fur- 
nace at such a time that the completion of the run 
will come at about the time of shutting off the fur- 
naces at night, so that the boxes can be left in until 
morning. This arrangement, however, is not always 
possible, and they must be removed from the fur- 



MISCELLANEOUS WORK. 367 

nace when heated long enough and buried in very- 
hot sand or ashes. 

Pieces 2"Xi"X6" should be held at the annealing 
temperature for about three hours. If very much 
larger than 2"Xi" the time should be increased 
somewhat, always avoiding long heats from the time 
the pieces are uniformly heated to the proper tem- 
perature. Always avoid overheating. If the tem- 
perature is raised much above 1500° F. hardness 
results, as it is approaching the temperature where 
the changes take place in the steel that produces 
hardness even if slow cooling is resorted to. Never- 
theless, if the heats do exceed 1500° F. slower cooling 
must be resorted to. 

To Anneal Without Discoloring. — If it is necessary, 
or desirable to anneal articles having polished sur- 
faces without oxidizing or discoloring them, it may 
be done by taking a piece of gas pipe of convenient 
size and length and thread both ends. On one end 
permanently screw a cap having one or two -^'^ 
holes drilled through it. The cap to go on the other 
end should be drilled and threaded to receive a |" 
gas pipe. The articles to be- annealed should be 
placed in the pipe, the cap screwed on and the whole 
placed in the furnace with the end that is to receive 
the I" pipe towards the front. The small pipe 
should be screwed to place and connected with an 
illuminating gas supply, as shown in Fig. 335. When 
the gas is turned on it should be immediately lighted 
at the opposite end of the pipe as it escapes from the 
small holes. 

The furnace heat should be turned on and the 



368 



FORGE-PRACTICE. 



operation carried on as in ordinary annealing of 
high-speed steel. When the pieces have been heated 
for the proper length of time the furnace heat may be 
shut off but the gas should be allowed to pass through 
the tube and burn until the pieces are cooled to below 
400° F. 

The gas passing through the pipe mixes with the 
air in the pipe and carries it out before an oxidizing 
temperature is reached, after which the flow of gas 
excludes all air, and as oxidation cannot take place 
unless air is present the surfaces will be clear and free 
from oxide. 



L 



Gas Pipe 




Fig. 335. 



A modification of the process just described con- 
sists in placing a small quantity of resin in the bot- 
tom of the hardening box, packing the work in the 
box surrounding each piece with powdered charcoal 
and then placing another small amount of resin on 
top. The cover should have a few small holes 
drilled through it to allow the gas to escape and 
should be securely sealed and the process carried on 
as in ordinary annealing. This method is also em- 
ployed in annealing articles made from carbon steel 
and when discoloration of surfaces is undesirable. 

Quick Annealing. — While fairly good results are 
sometimes obtained by rapid annealing, the prac- 



MISCELLANEOUS WORK. 369 

tice is one the writer does not advocate, but like a 
number of other practices which cannot be encour- 
aged there are times when it must be resorted to. A 
tool may be heated very slowly to a low red and buried 
in lime, ashes, asbestos, or sand that has been heated 
very hot and allowed to cool very slowly. A method 
employed by an acquaintance consists in heating as 
described above and plunging in water at a tem- 
perature of 200° F. 

Lathe, planer, and similar tools should be an- 
nealed after forging and before hardening. As the 
object of this annealing is to overcome forging strains 
which otherwise would manifest themselves when 
the piece is hardened, it may be accomplished by 
allowing them to cool down to a black after forging 
then re-heating to a low red and placing in a warm 
dry place and leaving until cold. 

Hardening High-Speed Steel. — There are many 
makes of high-speed steels on the market, some of 
which require special treatment in hardening. The 
majority, however, respond to the same treatment 
and it is with this class we shall deal when consider- 
ing the treatment necessary to obtain good results. 
The furnace used has a great deal to do in obtaining 
the right temperature. In some instances those 
designed for use in heating carbon steels can be used 
with good results in treating high-speed steel, but as 
a rule specially designed furnaces should be used. 

Coke furnaces properly made and tended are used 
with good results in some shops, but generally those 
burning gas or oil give best results and do not have 
the interruption necessary when cleaning and replen- 



370 FORGE- PRACTICE. 

ishing coke fires. As extremely high heats are neces- 
sary two or more furnaces should be used. The 
pieces should be pre-heated before placing in the 
high temperature furnace, or the steel will be weak- 
ened or ruptured. The pre-heating should be com- 
paratively slow, and to a temperature of about 
1500° F., when the pieces should be transferred to 
the high temperature furnace and rapidly heated 
the desired amount. This temperature necessarily 
varies according to the character of the tool. Taps, 
milling cutters, and other tools having slender pro- 
jecting teeth cannot be heated to as high a tempera- 
ture as ordinary lathe, planer, and similar tools. 
For the former, if made from most of the standard 
American high-speed steels, a temperature of 2250° 
to 2450° F. is recommended. While most lathe, 
planer and similar tools to be used for rough, heavy 
work, and whose design allows of grinding after 
hardening, should be heated nearly to the melting 
point; in fact in many cases it is advisable to heat 
until the edges and corners "drip," melting does 
not occur, in most high-speed steels, below a tem- 
perature of 2550° F. Where grinding is not allow- 
able after hardening slightly lower heats must be 
observed. 

Fig. 336 shows a furnace provided with a preheat- 
ing chamber immediately above the high-tempera- 
ture chamber. The waste gases from the lower 
chamber heat the upper one, effecting a considerable 
saving in fuel. After the furnace has been in opera- 
tion for some time the upper chamber may become 
too hot for pre-heating extremely complicated tools 



MISCELLANEOUS WORK. 



371 



in which case the tools may be placed on top of the 
furnace and transferred to the pre-heating chamber 
afterward. 

Fig. 337 shows a furnace having three chambers, 
the upper one being used in drawing the temper of 
tools or for cold steel until heated somewhat, and 




Fig. 336. 



before placing in the second, or pre-heating 
chamber. 

Electric Furnaces. — Excellent results are claimed 
by some from the use of electrically heated furnaces, 
especially in the treatment of certain classes of small 
tools. The cost of operating this type is apt to be 
rather high. 



372 



FORGE-PRACTICE. 



Lead Pot.— Lead heated white hot in a crucible 
was formally used very extensively in heating high- 
speed steel. Its use has given way to the barium 




Fig. 337. 



chloride process of heating in a few plants, and to 
the especially designed high-speed steel furnaces 
in most shops. However, it is employed in a few 
places in getting the final heats on milling cutters 



MISCELLANEOUS WORK. 373 

and similar tools. The tendency of the lead to 
rapidly oxidize at high temperatures may be over- 
come to a degree by keeping the surface covered 
with finely broken wood charcoal. A very serious 
objection to the use of the lead bath is the poisonous 
gases given off by it. As these gases are heavier 
than air it is difficult to conduct them away by any 
ventilating system that will not cool the lead. 

Salt Baths. — ^Various salts are used as heating 
baths for high-speed steel. These salts are held in 
crucibles in some form of specially designed furnace 
using coal, gas, coke or oil as fuel. Generally speak- 
ing, gas and oil give best results as a more uniform 
heat can be obtained. Specially designed electrically 
heated furnaces are used in connection with salt 
baths and excellent results are claimed by the makers, 
and by some users. Before deciding to install any 
electrically heated furnace the reader is advised to 
get in touch with parties who have had them in 
constant use on a commercial basis for some time and 
get their opinions as to their relative value and cost 
of maintenance. When making such inquiries it is 
well to bear in mind the fact that an electric fur- 
nace can be operated much more economically by a 
firm generating electricity on a large scale, or by one 
having a constant water power used for generating 
purposes. 

It is undoubtedly true that electrically heated 
furnaces can have their temperatures more accu- 
TSitely controlled than those heated by other means, 
especially when heating small articles. Some users, 
however, claim that the temperatures of such fur- 



374 FORGE-PRACTICE. 

naces fluctuate more when large pieces are immersed 
than is the case when gas or oil is used as fuel. It is 
also claimed by some that under certain conditions 
steel heated in electrically heated baths shows a 
decided tendency to pitted surfaces. 

When it is necessary to use two separate furnaces in 
heating they should, if possible, be located near each 
other to avoid cooling of light sections and the oxi- 
dation resulting from exposing the steel to the air 
when transferring from one to the other. 

As a rule it is advisable to anneal articles made 
from high-speed steel before they are heated for 
hardening. This is especially true of lathe, planer, 
and similar tools. Annealing relieves forging and 
other strains which are liable to manifest themselves 
when the piece is hardened. It is always best to 
anneal reworked tools before hardening. In one 
factory it was found that tools used in removing 
stock from the inside of projectiles when worn below 
size could be heated to a forging temperature flatted 
and ground to size and re-hardened, but their life 
was only about 40 per cent of that shown by new 
tools. Investigation showed that after being flatted 
they were ground and hardened without annealing. 
Orders were given to anneal after forging, as a result 
the tools were found to be 95 per cent efficient. 

At the present time the customary method of 
cooling high-speed steel when hardening is to dip in 
an oil bath rather than to cool in a blast of air. 
Cotton-seed oil, or fish oil works well as a quenching 
medium for some classes of tools, while others show 
better results if dipped in one of the lighter oils. 



MISCELLANEOUS WORK. 375 

Kerosene used alone, or added to some of the heavier 
oils is used in some hardening plants with excellent 
results. Extreme care should be exercised if kero- 
sene is used. The heated steel should be passed 
down through the surface so that all portions of 
the heated steel are completely covered to prevent 
the oil catching fire. If this bath is used precautions 
that will prevent burns and fires should be observed. 

Pack Hardening High-Speed Steel. — While lathe, 
planer and similar tools show best results when heated 
to the highest temperature possible without melting, 
and, in fact, when it can be done the temperature 
should be high enough to cause the edges to drip. 
Such heats are not possible when treating taps, 
formed milling cutters, punch-press dies, forming 
tools and similar articles. Experience shows that 
such tools give excellent results when pack hardened. 
When employing this method the tools should be 
packed in charred leather and run at a temperature 
ranging from 1750° to 2200° F. according to the 
character of the tool and the use to which it is to be 
put. 

Milling cutters and similar tools whose design 
allows of grinding after hardening and which are to be 
used for heavy roughing cuts may be heated higher 
than the temperatures mentioned above, the heats 
ranging from 2250° to 2350° F., while those to be 
used for light and finishing cuts may not require 
more than 2100° F. Threading dies, taps, reamers 
and other tools to be subjected to torsional (twisting) 
strains, require a temperature of 1950° to 2150° F., 
chisels, some classes of piercing punches and other 



376 FORGE-PRACTICE. 

tools that are to receive repeated shocks should not 
be heated above 1800° F. and in case of very severe 
usage not above 1750° F. 

Cooling. — Pack-hardened high-speed steel tools 
should not be quenched in an air blast, but in oil. 
For many tools a light lard oil works well, but for 
general use cotton-seed oil, or a commercial hardening 
oil is best. 

The pieces should be worked around well in the 
bath and allowed to remain until cold. The cause of 
failure many times can be traced to insufficient move- 
ment of the piece in the bath. This is especially true 
of large tools, milling-machine cutters, and punch- 
press blanking dies where the vapors are liable to 
lodge and prevent the oil reaching the essential por- 
tions. 

As the melting point of cast iron is comparatively 
low it is not advisable to use boxes made from this 
material when pack hardening high-speed steel as 
they are liable to give out quickly. The most satis- 
factory box is one made from boiler plate, or similar 
material. 

The length of time pieces should be exposed to the 
temperatures mentioned varies from one to four 
hours according to the size of the piece and the use 
to which it is to be subjected. Tools hardened by 
this method give better results in use than if heated 
in the open fire. 



TABLES. 



TABLE I. 

Circumferences and Areas of Circles. 



Diam- 


Circumfer- 


Area. 


Diam- 


Circumfer- 


Area. 


eter. 


ence. 




eter. 


ence. 




i 


•7854 


.0490 


3 


9.4248 


7.0686 


Ye 


.9817 


.0767 


i 


9-8175 


7.6699 


1 


I.1781 


.1104 


i 


10.210 


8.2958 


^6 


1-3744 


•1503 


1 


10 .603 


8.9462 


i 


1.5708 


.1963 


* 


10 .996 


9 .6211 


"X, 


I. 7671 


.2485 


f 


11.388 


10.321 


1 


I 9635 


.3068 


1 


II. 781 


II .045 


% 


2.1598 


•3712 


i 


12.174 


11-793 


i 


2.3562 


•4417 


4 


12 . 566 


12 . 566 


% 


2-5525 


■5184 


i 


12.959 


13-364 


^ 


2.7489 


.6013 


i 


13-352 


14.186 


% 


2.9452 


.6902 


t 


13-744 


15033 


r 


3.1416 


•7854 


^ 


14-137 


1 5 ■ 904 


Ye 


3-3379 


.8866 


1 


14.530 


16 .800 


i 


3-5343 


.9940 


f 


14.923 


17.728 


% 


37306 


1. 1075 


i 


15.315 


18.665 


i 


3.9270 


I . 2272 


5 


15.708 


19-635 


^6 


4-1233 


1-3530 


f 


16 . lOI 


20.629 


f 


4-3197 


I .4849 


i 


16.493 


21 .648 


^6 


4 - 5160 


I .6230 


f 


16.886 


22 .691 


i 


4.7124 


I. 7671 


h 


17.279 


23-758 


% 


4.9087 


1-9175 


f 


17.671 


24-850 


f 


5-1051 


2.0739 


f 


18.064 


25-967 


% 


5-3014 


2.2365 


i 


18.457 


27 . 109 


f 


S-4978 


2.4053 


6 


18.850 


28.274 


% 


5 -6941 


2 .5802 


i 


19.242 


29.465 


1 


5-8905 


2 .7612 


i 


19.635 


30 .680 


% 


6.0868 


2 .9483 


1 


20 .028 


31-919 


2 


6.2832 


3.1416 


h 


20 .420 


33-1S3 


3^6 


6-4795 


3.3410 


f 


20.813 


34-472 


i 


6.6759 


3-5466 


* 


21 . 206 


35.785 


^6 


6.8722 


3-7583 


i 


2 1 .598 


37.122 


i 


7.0686 


3-9761 


7 


21 .991 


38. 485 


,¥6 


7-2649 


4 . 2000 


1 


22.384 


39-871 


1 


7-4613 


4.4301 


i 


22.776 


41 . 282 


JTe 


7.6576 


4 .6664 


t 


23.169 


42.718 


\ 


7-8540 


4-9087 


^ 


23.562 


44-179 


% 


8.0503 


5-1572 


f 


23.955 


45-664 


f 


8.2467 


5-4119 


i 


24.347 


47-173 


% 


8.4430 


5.6727 


i 


24.740 


48.707 


f 


8.6394 


5 -9396 


8 


25-133 


50.265 


% 


8-8357 


6 . 2126 


1 


25-525 


5 1 . 849 


i 


9.0321 


6 .4918 


i 


25.918 


53.456 


% 


9.2284 


6.7771 


t 


26.311 


55-088 



379 



38o 



TABLES. 



TABLE I— (Continued). 
Circumferences and Areas of Circles. 



Diam- 
eter. 


Circumfer- 
ence. 


Area. 


Diam- 
eter. 


Circumfer- 
ence. 


Area. 


8i 


26 . 704 


56.745 


i6i 


51-051 


207.39 


f 


27 .096 


58.426 


* 


51-836 


213.82 


f 


27.489 


60 . 132 


1 


52 .622 


220.35 


i 


27.882 


61.862 


17 


53-407 


226 .98 


9 


28.274 


63.617 


i 


54-192 


233-71 


i 


28.667 


65-397 


h 


54-978 


240.53 


i 


29 .060 


67 . 201 


1 


55-763 


247-45 


t 


29-452 


69 .029 


18 


56-549 


254-47 


h 


29.845 


70.882 


i 


57-334 


261.59 


f 


30.238 


72 . 760 


^ 


58.119 


268.80 


f 


30.631 


74 .662 


1 


58.905 


276 . 12 


1 


31.023 


76-589 


19 


59-690 


283-53 


lO 


31 .416 


78. 540 


i 


60 .476 


291 .04 


1 


31 .809 


80.516 


h 


61 .261 


298.65 


i 


32 . 201 


82.516 


f 


62 .046 


306.35 


1 


32.594 


84.541 


20 


62.832 


314.16 


* 


32.987 


86.590 


i 


63.617 


322 .06 


1 


33.379 


88.664 


h 


64.403 


330.06 


f 


33-772 


90.763 


f 


65.188 


338.16 


i 


34.165 


92.886 


21 


65-973 


346.36 


II 


34.558 


95-033 


i 


66.759 


354-66 


i 


34-95° 


97-205 


h 


67-544 


363-05 


i 


35-343 


99.402 


f 


68.330 


371-54 


f 


35-736 


lOI .62 


22 


69.115 


380.13 


i 


36.128 


103.87 


i 


69 . 900 


388.82 


f 


36.521 


106 . 14 


h 


70.686 


397-61 


f 


36.914 


108.43 


f 


71.471 


406 .49 


i 


37-306 


110.75 


23 


72.257 


415-48 


12 


37-699 


113. 10 


i 


73-042 


424.56 


i 


38.4S5 


117.86 


i 


73-827 


433-74 


* 


39.270 


122.72 


f 


74-613 


443.01 


1 

4 


40.055 


127.68 


24 


75-398 


452.39 


13 


40 .841 


132.73 


i 


76.184 


461.86 


i 


41 .626 


137-89 


h 


76.969 


471-44 


h 


42.412 


143-14 


i 


77-754 


481 . II 


1 


43-197 


148.49 


^5, 


78.540 


490.87 


14 


43-982 


153.94 


i 


79-325 


500.74 


i 


44.768 


159-48 


i 


80 . 1 II 


510.71 


i 


45-553 


165-13 


4 


80.896 


520.77 


f 


46.338 


170.87 


26 


81.681 


530.93 


15 


47-124 


176.71 


i 


82.467 


541.19 


1 


47-909 


182.65 


h 


83-252 


551-55 


^ 


48.695 


188.69 


f 


84.038 


562 .00 


f 


49-480 


194.83 


27 


84.823 


572.56 


16 


50.265 


201 .06 


i 


85.608 


583.21 



TABLES. 



381 



TABLE I— {Continued). 
Circumferences and Areas of Circles. 



Diam- 


Circumfer- 


Area. 


Diam- 


Circumfer- 


Area. 


eter. 


ence. 




eter. 


ence. 




27i 


86.394 


593-96 


38f 


121.737 


I179-3 


f 


87.179 


604.81 


39 


122 .522 


1194.6 


28 


87965 


615-75 


\ 


123.308 


1210.0 


i 


88,750 


626. So 


\ 


124.093 


1225.4 


1 


89-535 


637-94 


\ 


124.878 


1241 .0 


f 


90.321 


649 . 18 


40 


125.664 


1256 .6 


29 


91 . 106 


660 . 52 


\ 


126 .449 


1272.4 


i 


91 .892 


671 .96 


\ 


127-235 


1288.2 


i 


92.677 


683.49 


\ 


128 .020 


1304.2 


f 


93.462 


695-13 


41 


128.805 


1320.3 


3° 


94.248 


706.86 


\ 


129.591 


1336.4 


i 


95033 


718.69 


\ 


130.376 


1352-7 


^ 


95.819 


730.62 


\ 


131 .161 


1369.0 


f 


96 .604 


742.64 


42 


131-947 


1385-4 


31 


97-389 


754-77 


i 


132.732 


1402 .0 


i 


98.175 


766.99 


\ 


133-518 


1418.6 


f 


98 . 960 


779-31 


! 


134-303 


1435-4 


f 


99.746 


791-73 


43 


135.088 


1452.2 


32^ 


100.531 


804. 25 


\ 


135-874 


1469 .1 


i 


lOI . 316 


816.86 


\ 


136.659 


1486.2 


i 


102 . 102 


829.58 


\ 


137-445 


1503-3 


f 


102 .887 


842.39 


44 


138.230 


1520. 5 


^-^. 


103.673 


855-30 


\ 


139-015 


1537-9 


J 


104 .458 


868.31 


\ 


139.801 


1555-3 


h 


105 -243 


881 .41 


\ 


140 . 586 


1572.8 


I 


106 .029 


894 .62 


45 


141-372 


1590-4 


34 


106 . 814 


907.92 


\ 


142.157 


1608.2 


^ 


107 . 600 


921.32 


\ 


142 .942 


1626 .0 


1 


108.385 


934.82 


\ 


143.728 


1643-9 


f 


109 . 170 


948.42 


46 


144-513 


1661 .g 


35 


109 . 956 


962 . 1 1 


\ 


145-299 


1680 .0 


i 


no . 741 


975-91 


\ 


146 .084 


1698.2 


i 


III .527 


989.80 


1 


146 .869 


1716.5 


f 


I 12 . 312 


1003 .8 


47 


147-655 


1734-9 


36 


113.097 


1017.9 


\ 


148 .440 


1753-5 


i 


113-883 


1032. 1 


\ 


149 . 226 


1772.1 


J 


114.668 


1046.3 


■4 


150. Oil 


1790 .8 


i 


115-454 


1060 .7 


48 


150.796 


1809 .6 


37 


116.239 


1075 .2 


\ 


I5I-5S2 


1828.5 


1 


117 .024 


1089.8 


\ 


152-367 


1847-5 


J 


117 .810 


1104.5 


\ 


153-153 


1S66.5 


1 


118.596 


1 1 19 . 2 


49 


153-938 


1885.7 


38 


119. 381 


1134-1 


\ 


154-723 


1905 .0 


i 


120 . 166 


U49.1 


\ 


155-509 


1924.4 


i 


120 .951 


1 164 . 2 


\ 


156.294 


1943-9 



382 



TABLES. 



TABLE I— (Continued) . 
Circumferences and Areas of Circles. 



Diam- 
eter. 


Circumfer- 
ence. 


Area. 


Diam- 
eter. 


Circumfer- 
ence. 


Area. 


50 


157.080 


1963-5 


62J 


196.350 


3068.0 


i 


157-865 


1983.2 


63 


197 .920 


3117.2 


i 


158 .650 


2003 .0 


^ 


199.491 


3166.9 


f 


159-436 


2022 .8 


64 


201 .062 


3217.0 


51 


160 . 221 


2042 . 8 


h 


202.633 


3267.5 


i 


161 .007 


2062 . 9 


65 


204 . 204 


3318.3 


i 


161 . 792 


2083.1 


i 


205.774 


3369.6 


f 


162.577 


2103.3 


66 


207.345 


3421.2 


52 


163.363 


2123.7 


h 


208 .916 


3473-2 


i 


164 . 148 


2144.2 


67 


210 .487 


3525.7 


h 


164.934 


2164.8 


h 


212 .058 


3578.5 


f 


165.719 


2185.4 


68 


213 .628 


3631-7 


53 


166 . 504 


2206 . 2 


i 


215.199 


3685.3 


i 


167 . 290 


2227 .0 


69 


216 . 770 


3739.3 


h 


168 .075 


2248 .0 


h 


218.341 


3793.7 


f 


168.861 


2269 . 1 


70 


219 .911 


3848. 5 


54 


169 .646 


2290 . 2 


h 


221 .482 


3903.6 


i 


170.431 


2311-5 


71 


223-053 


3959-2 


^ 


171. 217 


2332.8 


i 


224 .624 


4015.2 


]: 


172 .C02 


2354.3 


72 


226 . 195 


4071.5 


55, 


172.788 


2375-8 


i 


227.765 


4128.2 


i 


173-573 


2397-5 


73 


229.336 


4185.4 


^ 


174.358 


2419 . 2 


h 


230.907 


4242.9 


i 


175-144 


2441 .1 


74 


232.478 


4300.8 


56 


175.929 


2463.0 


i 


234.049 


4359.2 


i 


176.715 


2485.0 


75 


235-619 


4417.9 


^ 


177.500 


2507 . 2 


i 


237.190 


4477.0 


i 


178.285 


2529.4 


76 


238-761 


4536.5 


57 


179.071 


2551-8 


i 


240.332 


4596.3 


i 


179.856 


2574-2 


77 


241 .903 


4656.6 


i 


180 .642 


2596.7 


h 


243-473 


4717.3 


f 


181 .427 


2619 .4 


78 


245 .044 


4778.4 


58 


182 .212 


2642 . 1 


i 


246.615 


4839.8 


i 


182.998 


2664.9 


79, 


248.186 


4901 .7 


h 


183-783 


2687.8 


* 


249.757 


4963-9 


i 


184.569 


2710.9 


80 


251.327 


5026.5 


59 


185.354 


2734.0 


*- 


252.898 


5089.6 


i 


186.139 


2757.2 


81 


254.469 


5153-0 


i 


186.925 


2780.5 


i 


256 .040 


5216.8 


f 


187 .710 


2803.9 


82 


257.611 


5281.0 


60 


188.496 


2827.4 


h 


259.181 


5345-6 


h 


190 .066 


2874.8 


83 


260 . 752 


5410.6 


61 


191.637 


2922 . 5 


h 


262.323 


5476-0 


i 


193.208 


2970 .6 


84 


263.894 


5541-8 


62 


194.779 


3019. I 




265.465 


5607.9 



TABLES. 



383 



TAB LE I — (Continued) . 
Circumferences and Areas of Circles. 



Diam- 


Circumfer- 


Area. 


Diam- 


Circumfer- 


Area. 


eter. 


ence. 




eter. 


ence. 




^5, 


267.035 


5674.5 


93 


292 . 168 


6792.9 


h 


268.606 


5741.5 


h 


293.739 


6866.1 


86 


270.177 


5808.8 


94 


295.310 


6939.8 


\ 


271.748 


5876.5 


h 


296.881 


7013.8 


87 


273-319 


5944.7 


95 


298.451 


7088.2 


\ 


274.889 


6013 . 2 


h 


300 .022 


7163.0 


88 


276 .460 


6082.1 


96 


301.593 


7238.2 


h 


278.031 


6151.4 


\ 


303.164 


7313.8 


89 


279 .602 


6221 . 1 


97 


304.734 


7389.8 


h 


281 .173 


6291 .2 


\ 


306.305 


7466 .2 


90 


282.743 


6361 .7 


98 


307.876 


7543.0 


i 


284.314 


6432.6 


h 


309.447 


762c , I 


91 


285.885 


6503-9 


99 


311 .018 


7697.7 


h 


287.456 


6575.5 


h 


312.588 


7775.6 


92 


289 .027 


6647 .6 


100 


314-159 


7854.0 


i 


290.597 


6720 . 1 









384 



TABLES. 



TABLE II. 

Temperatures to which Hardened Tools should be Heated 
TO Properly "Draw the Temper," together with 
THE Colors of Scale appearing on a Polished-steel 
Surface at those Temperatures, and other Means 
of Detecting Proper Heating. 



Kind of Tool. 


Temper- 
ature , 
Fahr. 


Color of 
Scale. 


Action of 
File. 


Other Indi- 
cations. 


Scrapers for ordi- 


200° 






Water dries 


nary use. 








quickly. 


Burnishers. 




Very pale 


Can hardly 


L ar d- oi 1 


Light turning and 


430° 


yellow. 


be made 


smokes 


finishing tools. 






to catch. 


slightly. 


Engraving-tools. 






Can be 




Lathe-tools. 






made to 




Milling-cutters. 


460° 


Straw - yel- 


catch 




Lathe- and planer- 




low. 


Avith dif- 




tools for heavy 






ficulty. 




work. 










Taps. 










Dies for screw-cut'g. 










Reamers. 










Punches. 










Dies. 










Flat drills. 










Wood- working tools. 


500° 


Brown-yel- 






Plane-irons. 




low. 






Wood-chisels. 










Wood-turning tools. 










Twist drills. 










Sledges. 










Bl'ksmiths' ham'rs 










Cold-chisels for very 


530° 


Light pur- 


Scratches. 




light work. 




ple. 






Axes. 


550° 


Dark pur- 






Cold-chisels for or- 




ple. 






dinary use. 




Blue, ting'd 
slightly 
with red. 






Stone-cutting chisels 






Files with 




Carving-knives. 






great dif- 




Screw-drivers. 






ficulty. 




Saws. 










Springs. 


580° 


Blue. 


Files with 


Lard-oil 




610° 


Pale blue. 


difficulty. 


bums or 




630° 


Greenish 




flashes. 






blue. 









TABLES. 






TABLE 


III. 




Decimal 


Equivalents of Fractions of 


NE InCI 


From Kent's Mechanica 


I Engineer's Pocket-book. 


1/64 


.015625 


33/64 


•515625 


1/32 


.03125 


17/32 


•53125 


3/64 


.046875 


35/64 


•546875 


1/16 


.0625 


9/16 


•5625 


5/64 


.078125 


37/64 


■578125 


3/32 


•09375 


19/32 


■59375 


7/64 


•109375 


39/64 


■609375 


1/8 


•125 


5/8 


• 625 


9/64 


.140625 


41/64 


.640625 


5/32 


•15625 


21/32 


•65625 


11/64 


•171875 


43/64 


.671S75 


3/16 


•1875 


I1/16 


•6875 


13/64 


.203125 


45/64 


•703125 


7/32 


.21875 


23/32 


•71875 


15/64 


•234375 


47/64 


•734375 


1/4 


•25 


3/4 


•75 


17/64 


.265625 


49/64 


.765625 


9/32 


.28125 


25/32 


.78125 


19/64 


.296875 


51/64 


.796875 


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•3125 


13/16 


.8125 


21/64 


.328125 


53/64 


828125 


11/32 


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27/32 


•84375 


23/64 


•359375 


55/64 


•859375 


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61/64 


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COURSE OF EXERCISES IN FORGE WORK. 

What is suggested as a standard course of exer- 
cises is given below. 

A short talk should first be given covering the 
calculation of stock for simple bent work, rings, 
links, eyes, etc. 

The starting of the fire and fitting of tongs is 
then explained. 

Exercise i. Stock \"y.\"->i^" is drawn out to \" 
round, and this round stock is used to make 
the two following pieces of work. 
Exercise 2. Fig, 338. Eye Bend. 

Double Eye Bend. 
Twisted Gate Hook. 
Square Point and Eye Bend. 
Twisted Scriber. Before giv- 
ing this exercise a short talk should be given 
on the effect of high heats on tool steel. The 
scriber should be forged from an old file in 
order to give practice in the drawing out of 
tool steel. The scriber is tempered later in the 
course. 
Exercise 7. Fig. 342. Weldless Ring. 
Exercise 8. Fig. 355. Chain Hook. 
Exercise 9. Fig. 351. Bracket with Forged Corner. 

387 



Exercise 3. Fig. 339 
Exercise 4. Fig. 341 
Exercise 5. Fig. 342 
Exercise 6. Fig. 377 



388 FORGE-PRACTICE. 

Exercise 10, Practice Weld. This should be a sort 
of a faggot weld made by doubling over the 
end of a piece of scrap, the object being simply 
to determine the welding heat. 

Exercise 11. Fig. 357. Chain of Three Links. 

Exercise 12. Fig. 348. Flat Lap Weld. 

Exercise 13. Fig. 349. Angle Weld. 

Exercise 14. Fig. 347. Welded Ring. This and the 
hook made in Ex. 9 should each be joined to 
the chain by extra links, making a chain of 
five links with the hook on one end and the 
ring on the other. 

Exercise 15. Fig. 373. Welded Rings shrunk to- 
gether. 

Exercise 16. Fig. 358. Planer Bolt, make welded 
head. 

Exercise 17. Fig. 352. Hexagonal Head Bolt, 
upset head. 

Exercise 18. Fig. 354, Ladle. 

Exercise 19. Fig. 367. Taper Machine Key. 

Exercise 20. Fig. 368. Lever Arm. 

Exercise 21. Figs. 370, 371, or 372. Tongs. 

Exercise 22. Hardening Tool Steel. The stddent 
should be given an old file or piece of scrap 
tool steel to determine the proper hardening 
heat. This is done by drawing out the steel 
to about I'' square and hardening the end, 
which is then snapped off and the condition 
of the steel determined from the fracture. 
This should be repeated until the hardening 
heat can be hit upon every time. 

Exercise 23. Fig. 313. Cold Chisel. 



COURSE OF EXERCISES IN FORGE WORK. 389 

Exercise 24. Fig. 380. Center Punch. 

Exercise 25. Fig. 397. Cape Chisel. 

Exercise 26. Figs. 382 or 383. Thread Tool. 

Exercise 27. Fig. 384. Round Nose Tool. 

Exercise 28. Fig. 381. Side Tool. 

Exercise 29. Fig. 387. Boring Tool. 

Exercise 30. Fig. 385. Diamond Point. 

Exercise 31. Figs. 393, 394, 395, 396, or 399. Hot 

Chisel, Cold Chisel, Set Hammer, Flatter or 

Pattern-maker's Hammer. 
Exercise 32. Fig. 400. Spring. 
Exercise 33. Fig. 375. Brazed Ring. 

Many students will be able to cover much more 
ground than outlined above, and for such cases 
additional drawings are given. These additional 
exercises may be interpolated where the instructor 
sees fit. 

Additional drawings are also given in order that the 
course may be varied somewhat from term to term. 

No more than three pieces of stock should ever 
be allowed for any one exercise, and as a general 
rule the student should do the work with one. 
When more than one piece is used the work should 
be graded down accordingly. 

Talks should be given on Brazing, Case Hard- 
ening, Metallurgy of Bessemer, Open Hearth, and 
Crucible Steels and Wrought Iron. 

Considerable work should also be done in making 
sketches and stock calculations for large machine 
forgings, the sketches to show the different steps 
in the forging process. 



390 FORGE-PRACTICE. 

When a steam or power hammer is available old 
hammers, tools, etc., may be drawn out into bar 
stock for center punches, small chisels, etc. 

The tongs shown in the drawings may be made 
to good advantage under a steam or power 
hammer. 



COURSE OF EXERCISES IN FORGE WORK. 391 





Fig. 339 
DOUBLE EYE BEND 




^ Fig. 341 



TWISTED GATE HOOK 



392 



FORGE-PRACTICE. 




k%>k- 



->i<-%^ 




7I — ^ 






fa 



ijc 







COURSE OF EXERCISES IN FORGE WORK. 



393 






7^ 



> 










z 










o 


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uq 








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CO 




^ 






><^ 




(ti 




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fD 








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A 








T 


' 





-1 



■r- 




394 



FORGE-PRACTICE. 







^t- 



BRACKET WITH FORGED CORNER 
rig. 351 



Calculate dimensions of head 
by formula ^^--^^ 



3^ 




X x4 HEX. HEAD BOLT 



Fig. 352 




OPEN WRENCH Fig. 353 



COURSE OF EXERCISES IN FORGE WORK. 395 




FORGED EYE HOOK r*i i?/^ 



WELDED EYE HOOK 



.2V/1 >1 



fEM¥4€=}} 



CHAIN 
Fig. 357 



396 



FORGE-PRACTICE. 



Finish all over 



J 



-Length as required- 



rO 



1 ^—'- 



PLANER BOLT Fig, 358 




PLANUR STRAP No. 1 ^^S- 359 



,*^„- 



Lengtli as required - 



PLANER STRAP No. 2 
Fig. 360 



COURSE OF EXERCISES IN FORGE WORK. 



397 



I " r 




398 



rORGE-PRACTICE. 




COURSE OF EXERCISES IN FORGE WORK. 399 




(<-%'■ 



Fig. 366 
'C" CLAMP 

5^ 



^^ 






k-y^-><- 



-3^4- 



ii 



->-, ■'■>',xK- 



TAPER KEY Finish all over 
Fig. 367 




Fig. 369 
LEVER & HANDLE 



400 



FORGE-PRACTICE. 





COURSE OF EXERCISES IN FORGE WORK. 4OI 



Fig. 373 




Fig. 375 



Fig. 376 



BRAZED FLANGE 



402 



rORGE-PRACTICE. 





COURSE OP EXERCISES IN EORGE WORK. 403 




RIGHT HAND SIDE TOOL 



6-8 on new Tools 




THREAD TOOL N0.I 



EFCTION A-A 



-5-8 on new Tools- 



-L ^~" J r 



Fig. 383 



THREAD TOOL No. 2 



TI7 



-5-8 on new Tools- 




ROUND NOSE TOOL 



SECTION A-A 



404 



S"ORGE-PRACTICE 



Fig. 385 




Fig. 386 



Fig. 387 



CUTTING OFF TOOL 



COURSE OF EXERCISES IN FORGE WORK. 405 




FLAT SCRAPER 
(May be made fi'om old file ) Fig. 390 




J£ 



:mc::> 



HALF ROUND SCRAPER Fig. 391 
(May be made from old half round file as shown by dotted linos) 




4o6 



FORGE-PRACTICE. 




Fig. 393 BLACKSMITH'S HOT CHISEL 

BLACKSMITH'S COLD CHISEL 
Fig. 394 Make same way but shape end as shown 
by dotted line. 




154 SET HAMMER 



Fig. 395 





2>s FLATTER 



ri«. 396 



COURSE OF EXERCISES IN EORGE WORK. 407 




ROUND NOSE OR CENTERING CHISEL 




i__ 



PATTERN MAKER'S HAMMER 
Fig. 399 



d 



Give Spring Temper 
all over. 




INDEX„ 



Alloy steeis, 202, 203. 
Animal charcoal, 335. 
Annealing, in general, 266. 
, box, 269. 

" before hardening, 374. 

" copper and brass, 193. 

" high-speed steel, 364. 

" , overheating when, 268. 

' ' , prolonged heats in, 268. 

" , quick, 368. 

" , temperatures for, 266. 

" , imdesirable results when, 271, 

" , water, 273. 

" without discoloring, 367. 

Anvil, description of, 6. 

Baths, cooUng, 226. 

" for tempering, 247. 
Bending, 59. 

" cast-iron, 194. 
' ' duplicate work, 146. 
pipe, 188. 
Bessemer converter, two types of, 200. 

" steel, 200, 201. 
Bolts, general dimensions of, 77. 
cupping-tool for, 78. 
heading-tool for, 78. 
making of, 77. 
upset-head, 79. 
welded-head, 80. 
Bone for case hardening, 335. 
Borax used as a flux, 21. 
Boss on flange, forging of, 144. 

409 



4IO 



INDEX 



Boss on lever, forging of, iii. 
Bowls, making of, 88. 
Brace, or bracket, welded, iig. 
Brazing, flux used, i88. 

" , methods of, 185. 

" , process of, 184. 

" , spelter for, 186. 
Brine-bath, 233. 
Butt-weld, 34. 



Calculation of stock, see Stock calculation. 
Cape-chisel, forging and tempering of, 161. 
Carbon percentages for various tools, 206. 
Case hardening, 332. 

, animal-charcoal used in, 335, 
, barium-carbonate used in, 336. 

bath for color work, 345. 
, boxes for use in, 337. 
, carburizers for use in, 334. 
, charred-bone for use in, 335. 
, charred-leather for use in, 336. 
, cyanide of potassium for use in, 333, 357, 
, deep penetration in, 348. 

with gas as carburizer, 356. 
, examples of, 347. 
for strength, 354. 
large nuts, 348. 
, local, 351. 

, mixtures used in, 337. 
, oil bath for, 346. 
small pieces, 340. 
Cast-iron, bending of, 194. 
Causes of trouble when hardening, 322. 
Chain making, 30. 

" , stock required to make link, 48. 
" stop, forging of, 88. 
Changes in length of steel, when hardened, 262. 
Chisels, blacksmiths, hot and cold, 6. 

" " , forging and tempering, 180. 

I " " , grinding, 8. 

** , or cutters for steam-hammers, 123. 
Chrome-vanadium steel, 203. 



INDEX 411 



Coal, requirements of forge, 2. 

Coke fire, 214, 36Q. 

Cold-chisels, descriptions of blacksmiths, 7. 

" " , making of, 159. 

" " hardening and tempering, 160, 276. 
Cold-dropping dies, hardening, 316. 
Cooling with streams of water, 231. 
Cones, sentinel, 223. 
Connecting-rod, , forging of forked end, 104. 

" " " with steam-hammer, 1380 

" " , stock calculations for, 93. 

Copper, annealing of, 193. 
Copper-pipe, bending, 192. 
Course of exercises in forge work, 387. 
Crank-shaft, calculations of stock required, 91, 

" " , forging with steam-hammer, 135. 

" " " of single-throw, 90, 97. 

" " " " double-throw, 99. 

" " " " triple-throw, loi. 

Crucible tool-steel, carbon percentages, 206. 
Cupping-tools, for bolts, 78. 
Cutting-block, description of, 10. 
Cutting stock, methods, of, 9. 
Cyanide of potassium for case-hardening, ^^^t 3S7» 

Decalescence point, 258. 
Direct-flame furnace, 210. 
Disintegration, 326. 
Drop-forging dies, description of, 154. 

" " " ) hardening, 315. 

" " " for hot forming, 157. 

" " eye-bolts, 155. 

" " with steam-hammer, 158, 
Duplicate bending with block, 147. 
" jig, 152. 
" work, 146. 

Effect of high heats on steel, 196. 

Electric furnaces, 371. 

Exact temperatures when hardening, 239, 

Examples of hardening, 275. 

Eye, bending of, 64. 



412 INDEX 

Eye, weldless, making of, from flat stock, log. 
Eye-bolt, drop-forging of, 155. 

File finish, allowance for, 95. 
Fire, banking of, 4. 
' ' , building of, 2 . 
" , description of good, 3. 
" , oxidizing, 5. 
Flange, with boss, forging of, 143. 
Flux for brazing, 1S8. 

" , use of, in welding, 20. 
Forge, description of, i. 
Fork, welded, 119. 
Forked ends, forging of, 102, 107, 
Fullers, description of, 15. 

" , forging of, 182. 
Fuel for use in heating furnaces, 213., 
Furnaces, heating, 209. 
" , coke, 214. 
" , direct flame, 210. 
" , muffle, 209. 
" , preheating, 370. 
" , bottom-fired, 211, 
" , semi-muffle, 209. 
" , top-fired, 212. 

Gate-hook, making of, 68. 

Hammers, description of, 10. 

" , ball-penc, 178. 

" , forging and tempering of, 1740 

" , riveting, 176. 

" , sledge, 179. 
Hardening, 239. 

" and tempering, 256. 

" , brine-bath used in, 233. 

" , burnishing dies, 2S7. 

" carbon tool-steel, 239, 332. 

" , causes of trouble when, 322. 

*' cold-chisels, 160, 276. 

" cutting, or dinking-dies, 290, 

" curling-dies, 291. 



INDEX. 413 



Hardening dies, 279. 

" dies with thin sections, 283. 

" draw-broaches, 306. 

" drop-forging dies, 315. 

" forming and bending dies, 290, 

" , heats for, 239. 
" high-speed steel, 369. 

" large rings, 307. 

" , magnet used in, 258. 
" miUing-cutters, 296. 

" piercing-punches, 275. 

" punch-press dies, 279. 

" redrawing dies, 284. 

" rivet sets, 307. 

" spring-threading dies, 310. 

*' taps, 291. 

" thin cutters, 304. 

" threading dies, 295, 310. 

" with steam, 238. 

*' with vapor, 238. 

" with water-bath, 235. 

" with water sprays, 236, 238. 

Hardie, description of, 7. 

" , forging of, 180. 
Heading-tool for bolts, 78. 
Heating-furnaces, 209. 
Heat-recording instruments, 219, 
Heat-treatment of steel, 194. 
Hook, chain, 71. 
" , gate, 68, 
" , grab, 70. 
" , hoist, 75. 
" with welded eye, 74. 
Hot-chisel, description of, 7. 

" " , forging of, 180. 
High-speed steel, forging, 361. 

" " " tools, forms of, 363, 

Jump-weld, 35. 

Knuckles, forging various kinds of, 102. 



414 INDEX 

Ladles, making of, 86. 

Ladle shank, forging of foundry, ii4„ 

Laps in steel, 325. 

Lathe tools in general, 162. 

, boring, 167. 

, centering, 172. 

, cutting-off, 164. 

, diamond-point, 168. 

, finishing, 172. 

, internal thread, 168. 

, round-nose, 163. 

, side, 170. 

, thread, 163. 
Lead-bath for heating steel, 216, 372. 
Light in the hardening-room, 207. 
Long continued heats, effects of, 324. 

Machine-steel, 201. 
Magnet used in hardening, 258. 
Molders trowel, forging of, 117. 
MufHe-furnace, 209. 

Nickel-steel, 202. 
Nickel-chrome-steel, 203. 

Oil-tempering furnace, 247. 
Open-hearth steel, 200. 
Over anneahng, 323. 
Over heating, 324. 

" " , when hardening, 240. 
Oxide, formation of, on iron, 5. 
Oxidizing fire, 5. 
Oxygen, effect of on iron when heating, 5= 

Pack-hardening, 328. 

gauges, 331. 

" " high-speed steel, 375. 

" " , temperatures when, 330= 

" " , time exposure when, 330. 

Pipe-bending in general, 188. 

" " , copper, 192. 

" " , different methods, 190. 



INDEX 415 



Pipe-bending with jigs, 191, 1Q3. 

Piping, 325. 

Planer-tools, see Lathe-tools. 

Point, meaning of, 200. 

Pointing, precautions necessary, 52. 

Pre-heating high-speed steel, 370. 

" furnaces, 370. 

Punch, for steam-hammer, 141. 
Punching, methods of, and tools used, 58, 

" , tools for duplicate, 142. 
Pyrometer, 221. 

" ■ , calibrating of, 222, 224. 

Quick annealing, 368. 
Quick case-hardening, ^t,^. 

Recalescence point, 259. 

Redrawing dies, hardening, 284. 

Retarding the cooling of light sections, 240, 283. 

Reworking drop-forging dies, 322. 

Rings, amount of stock required, 46. 

, bending up, 63. 

, forging under steam-hammer, 139, 

, welding of flat stock, 32. 
" round stock, 29. 

" washer, ;^^. 

, weldless making of, no. 
Round-nosed chisels, 168. 

Salt baths, 373. 
Sand, uses of, as flux, 21. 
Scarfing for weld, object of, 23, 
Seams in steel, 325. 
Semi-mufiJe furnaces, 209. 
Sentinel cones, 222. 
Set-hammer, description of, 14. 

" " , making of, 181. 

Shaper-tools, see Lathe-tools. 
Shore sceroscope, 243. 
Shrinking, process of, 183. 
Sledges, description of, 11. 

" , hardening and tempering, 179. 



4l6 INDEX 

Socket wrench, forging of, io6. 
Spelter for brazing, iS6. 
Split work, shaping from thin stock, 107, 
Springing, 260. 
Spring-steel, welding of, 35. 
Spring-tempering, 310. 
Square corner, forging of, 60. 
Steam-hammer, description of, 120. 

" " , cutting work under, 127. 

" " , forging taper work with, 130. 

" " , general notes on, 126. 

" " , tongs for, 121. 

" " , tools and swages for, 120. 

" " , tools for cutting work with, 123. 

Steel, 199. 

" for milling cutters, 299. 

" for taps, 293. 

" " various tools, 205. 
Stock calculations, in general, 41. 

" " , for circles, 46. 

" " " connecting-rod, 92. 

" " " curves, 44. 

" " " links, etc., 48. 

" " " simple bends, 44. 

" " " single-throw crank, 91. 

" " " weldless ring, no. 

Straightening pieces that are sprung, 261. 

Table of temperatures for forging and hardening, 332. 

Tables, 379-385- 

Taper work with steam-hammer, 130, 145. 

Tempering, 246. 

Temper color chart, 247. 

Temperature of bath, 241. 

Temperature scales, 253. 

Tempering furnace, 247. 

" on hot plate, 250. 

" machine, 250. 

" in sand, 252. 

Testing hardened steel, 242. 
Tongs, description of, 12. 
" , fitting of, 13. 



INDEX 

Tongs for round stock, forging of, 83. 
steam-hammer work, 121. 

" , forging bolt, 84. 

" , " of light hand, 81. 

" , " "pick-up, 84. 

" , " ", with welded handles, 84. 

" , " with steam-hammer, 133. 
Tool forging in general, 160. 
Tool-steel, 204. 
Toughening, 255. 

Troubles experienced when hardening mills, 305. 
Trowel, forging of moulders, 117. 
Truing-up work, 54. 

" " , under steam-hammer, 133. 

Tuyere, use, and description of, i. 
Twisting for ornamental work, 66. 
" gate-hook, 70. 

Underfired furnace, 211. 
Undesirable results when annealing, 271. 
Uniform heating, 240, 324. 
Upsetting, definition and methods of, 55= 
tool-steel, 327. 

Value of experiments, 263. 

Water-annealing, 273. 
" baths, 233, 235. 
" sprays, 238. 
Weight of bar iron and steel, 386. 

forgings, calculations of, 94. 
Weld, angle, flat stock, 37. 

" , butt, 34. 

" , chain, ig, 30. 

" , faggot, or pile, 22. 

" , flat-lap-, 24. 

" , fork, iig. 

" , iron to steel, 36. 

" , jump, 35. 

" , ring, flat stock, 32. 

" , " , round stock, 29. 

" , round lap-, 28. 



417 



41 8 INDEX 

Weld, split, for heavy work, 36. 
" , split, for light work, 35. 

, spring-steel, 35. 
" , "T", flat stock, 38. 
" , "T", round stock, 39. 
" , washer, or flat ring, 33. 
Welding in general, 17. 

' ' , allowance of stock for, 260 
" , scarfing for, 23. 
" spring-steel, 35, 40. 
" tool-steel, 39. 
" , uses of flux in, 20. 
Wood-charcoal as a carburizer, 336. 
Wrench for twisting crank-shaft, 100= 
" , forging of open-end, 105. 
" , " " socket, 106. 




Subjects Related to this Volume 

For convenience a list oF the Wiley Special Subject Catalogues, 
envelope size, has been printed. These are arranged in groups 
— each catalogue having a key symbol. (See Special Subject 
List Below). To obtain any of these catalogues, send a 
postal using the key symbols of the Catalogues desired. 



List of Wiley Special Subject Catalogues 

1 — ^Agriculture. Animal Husbandry, Dairying. Industrial 
Canning and Preserving. 

2 — Architecture. Building, Masonry. 

3 — Business Administration and Management. Law. 

Industrial Processes: Canning and Preserving; Oil and Gas 
Production; Paint; Printing; Sugar Manufacture; Textile. 

CHEMISTRY 

4a General; Analytical, Qualitative and Quantitatl^'«; Inorganic; 

Organic. 
4b Electro- and Physical; Food and Water; Industrial; Medical 

and Pharmaceutical; Sugar. 

CIVIL ENGINEERING 

5a Unclassified and Structural Engineering. 

5b Materials and Mechanics of Construction, including; Cement 
and Concrete; Excavation and Earthwork; Foundations; 
Masonry. 

5c Railroads; Surveying. 

5d Dams; Hydraulic Engineering; Pumping and Hydraulics; Irri- 
gation Engineering; River and Harbor Engineering; Water 
Supply. 

(Over) 



CIVIL ENGINEERING— Con/im«eJ 
5e Highways; Municipal Engineering; Sanitary Engineering; 
Water Supply. Forestry. Horticulture, Botany and 
Landscape Gardening. 



6 — Design. Decoration. Drawing: General; Descriptive 
Geometry; Kinematics; Mechanical. 

ELECTRICAL ENGINEERING— PHYSICS 

7 — General and Unclassified; Batteries; Central Station Practice; 
Distribution and Transmission; Dynamo-Electro Machinery; 
Electro-Chemistry and Metallurgy; Measuring Instruments 
and Miscellaneous Apparatus. 



8 — Astronomy. Meteorology. Explosives. Marine and 
Naval Engineering. Military. Miscellaneous Books. 

MATHEMATICS 
9 — General; Algebra; Analytic and Plane Geometry; Calculus; 
Trigonometry; Vector Analysis. 

MECHANICAL ENGINEERING 
10a General and Unclassified; Foundry Practice; Shop Practice. 
10b Gas Power and Internal Combustion Engines; Heating and 

Ventilation; Refrigeration. 
10c Machine Design and Mechanism; Power Transmission; Steam 

Power and Power Plants; Thermodynamics and Heat Power. 
1 1 — Mechanics . 

12 — Medicine. Pharmacy. Medical and Pharmaceutical Chem- 
istry. Sanitary Science and Engineering. Bacteriology and 

Biology. 

MINING ENGINEERING 

13 — General; Assaying; Excavation, Earthwork, Tunneling, Etc.; 
Explosives; Geology; Metallurgy; Mineralogy; Prospecting; 
Ventilation . 



H 15 
















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